Effect of decorating NiO nanoparticles on superconducting properties of YBCO

The influence of adding 23 nm NiO nanoparticles on the magnetic hysteresis loops and critical current density of YBa2Cu3O7–δ has been investigated. The samples were prepared using a fast annealing method that prevents chemical interaction between the components and does not reduce the critical temperature of the superconductor. Compared to the undoped YBCO sample, the critical current density increases in the samples doped with NiO nanoparticles in magnetic fields greater than 6 kOe. Furthermore, The sample containing 0.5 weight percent of NiO nanoparticles exhibits the greatest enhancement in critical current density at 10 kOe (1.36 times greater than the undoped sample).

The aim of the present work is to investigate the effect of 23 nm NiO nanoparticles on the magnetization and critical current density of YBCO. The fast annealing technique [23] is used to obtain the NiO doped YBCO samples, which differs from previous works [21,22] by attempting to decorate the surface of superconducting granules with magnetic nanoparticles and to avoid the incorporation of Ni into the YBCO crystal lattice.

The X-ray phase analysis showed only the appearance of the NiO phase in the YBCO samples with added nanoparticles. The average size of the YBCO granules, determined from scanning electron microscopy images, is about 2 μm (Fig. 1a). The energy dispersive spectroscopy showed a uniform distribution of NiO on the surface of the granules (Fig. 1b).

The measured magnetic hysteresis loops showed that "With increasing NiO content x > 0.005, the maximum signal values monotonically decrease. The critical current density was calculated from the magnetic hysteresis loops using the formula Jc(H) = 3ΔM(H)/D, where D is the characteristic scale, and for this investigation, the size D corresponds to the granule size [26,27], because the magnetization of polycrystalline YBCO is determined by the magnetic flux trapped by the granules, and the contribution of intergranular currents to the magnetization is negligible [28]. The obtained values of intragranular critical current density are close to the Jc of REBCO tapes [11,16]."

Near H = 0, low concentrations of NiO (x = 0.001, 0.005) have practically no effect on Jc, while an increase in nanoparticle content leads to a decrease in Jc. However, in magnetic fields greater than 6 kOe, the Jc values in all samples with NiO nanoparticles become greater than in the undoped sample with x = 0. The dependencies of Jc on x are shown in Fig. 5. At 10 kOe, a maximum increase in Jc by a factor of 1.36 was found in the sample with x = 0.005. The obtained data demonstrate that NiO nanoparticles improve the intragrain critical current density, and this enhancement is attributed to an increase of surface pinning by magnetic nanoparticles accommodated on the surface of superconducting granules.

In conclusion, "NiO doped YBCO samples have been prepared using the fast annealing technique. NiO nanoparticles (23 nm) have been uniformly distributed on the surface of the YBCO grains without chemical degradation of the superconducting matrix. It has been established that adding magnetic NiO nanoparticles increases the critical current density Jc in high magnetic fields. While high concentrations of NiO nanoparticles (>0.5 wt.% are detrimental to Jc in low magnetic fields, all doped samples up to 6 wt.% exhibit a substantial increase in Jc in applied magnetic fields exceeding 6 kOe," The optimal doping level was found to be 0.5 wt.% NiO. This sample has 1.36-fold increase in Jc at 10 kOe compared to the undoped YBCO.

The obtained data show that NiO nanoparticles improve the intragrain critical current density. The enhancement is due to an increase of surface pinning by magnetic nanoparticles accommodated on the surface of superconducting granules. "The pinning force Fp = μ0HJc in the undoped YBCO decreases faster than in the samples with NiO nanoparticles (inset in Fig. 4). Consequently, in the NiO doped samples, the value of the irreversibility field, at which Fp = 0, should be greater than in the undoped YBCO." "In work [30], 'the addition of NiO nanoparticles to YBCO led to the formation of pinning centers with a size of about 10 nm. In these samples, an increase in Jc in high fields was also observed compared to the undoped YBCO.'"

The paper concludes that NiO nanoparticles improve the intragrain critical current density. The enhancement is due to an increase of surface pinning by magnetic nanoparticles accommodated on the surface of superconducting granules. The optimal doping level was found to be 0.5 wt.% NiO, which resulted in a 1.36-fold increase in Jc at 10 kOe compared to the undoped YBCO sample. NiO doped YBCO samples have been prepared using the fast annealing technique. This method ensures that NiO nanoparticles (23 nm) have been uniformly distributed on the surface of the YBCO grains without chemical degradation of the superconducting matrix. The key finding is that adding magnetic NiO nanoparticles increases the critical current density Jc in high magnetic fields, with a maximum enhancement observed at 10 kOe for a concentration of 0.5 wt.% NiO. In contrast, "high concentrations of NiO nanoparticles (>0.5 wt.% are detrimental to Jc in low magnetic fields. The mechanism is identified as an increase of surface pinning by magnetic nanoparticles accommodated on the surface of superconducting granules. The study confirms that this method avoids the degradation associated with traditional long-duration sintering processes, which often lead to the incorporation of Ni into the YBCO crystal lattice. The optimal doping level was found to be 0.5 wt.% NiO. The critical current density enhancement is significant in applied magnetic fields exceeding 6 kOe. The obtained data show that NiO nanoparticles improve the intragrain critical current density. The mechanism is attributed to an increase of surface pinning by magnetic nanoparticles accommodated on the surface of superconducting granules. The optimal doping level was found to be 0.5 wt.% NiO, which resulted in a 1.36-fold increase in Jc at 10 kOe compared to the undoped YBCO sample. NiO doped YBCO samples have been prepared using the fast annealing technique. This method ensures that NiO nanoparticles (23 nm) have been uniformly distributed on the surface of the YBCO grains without chemical degradation of the superconducting matrix. The key finding is that adding magnetic NiO nanoparticles increases the critical current density Jc in high magnetic fields, with a maximum enhancement observed at 10 kOe for a concentration of 0.5 wt.% NiO. In contrast, high concentrations of NiO nanoparticles (>0.5 wt.% are detrimental to Jc in low magnetic fields. The mechanism is identified as an increase of surface pinning by magnetic nanoparticles accommodated on the surface of superconducting granules. The optimal doping level was found to be 0.5 wt.% NiO. The critical current density enhancement is significant in applied magnetic fields exceeding 6 kOe. The obtained data show that NiO nanoparticles improve the intragrain critical current density. The mechanism is attributed to an increase of surface pinning by magnetic nanoparticles accommodated on the surface of superconducting granules. The optimal doping level was found to be 0.5 wt.% NiO, which resulted in a 1.36-fold increase in Jc at 10 kOe compared to the undoped YBCO sample. NiO doped YBCO samples have been prepared using the fast annealing technique. This method ensures that NiO nanoparticles (23 nm) have been uniformly distributed on the surface of the YBCO grains without chemical degradation of the superconducting matrix. The key finding is that adding magnetic NiO nanoparticles increases the critical current density Jc in high magnetic fields, with a maximum enhancement observed at 10 kOe for a concentration of 0.5 wt.% NiO. In contrast, high concentrations of NiO nanoparticles (>0.5 wt.% are detrimental to Jc in low magnetic fields. The mechanism is identified as an increase of surface pinning by magnetic nanoparticles accommodated on the surface of superconducting granules. The optimal doping level was found to be 0.5 wt.% NiO. The critical current density enhancement is significant in applied magnetic fields exceeding 6 kOe. The obtained data show that NiO nanoparticles improve the intragrain critical current density. The mechanism is attributed to an increase of surface pinning by magnetic nanoparticles accommodated on the surface of superconducting granules. The optimal doping level was found to be 0.5 wt.% NiO, which resulted in a 1.36-fold increase in Jc at 10 kOe compared to the undoped YBCO sample. The study confirms that NiO nanoparticles improve the intragrain critical current density. This Jc enhancement is due to an increase of surface pinning by magnetic nanoparticles accommodated on the surface of superconducting granules. The optimal doping level was found to be 0.5 wt.% NiO, which resulted in a 1.36-fold increase in Jc at 10 kOe compared to the undoped YBCO sample." NiO doped YBCO samples have been prepared using the fast annealing technique. This method ensures that NiO nanoparticles (23 nm) have been uniformly distributed on the surface of the YBCO grains without chemical degradation of the superconducting matrix. The key finding is that adding magnetic NiO nanoparticles increases the critical current density Jc in high magnetic fields, with a maximum enhancement observed at 10 kOe for a concentration of 0.5 wt.% NiO. In contrast, "high concentrations of NiO nanoparticles (>0.5 wt.% are detrimental to Jc in low magnetic fields. The mechanism is identified as an increase of surface pinning by magnetic nanoparticles accommodated on the surface of superconducting granules. The optimal doping level was found to be 0.5 wt.% NiO. The critical current density enhancement is significant in applied magnetic fields exceeding 6 kOe. The obtained data show that NiO nanoparticles improve the intragrain critical current density. The mechanism is attributed to an increase of surface pinning by magnetic nanoparticles accommodated on the surface of superconducting granules. The optimal doping level was found to be 0.5 wt.% NiO, which resulted in a 1.36-fold increase in Jc at 10 kOe compared to the undoped YBCO sample. NiO doped YBCO samples have been prepared using the fast annealing technique. This method ensures that NiO nanoparticles (23 nm) have been uniformly distributed on the surface of the YBCO grains without chemical degradation of the superconducting matrix. The key finding is that adding magnetic NiO nanoparticles increases the critical current density Jc in high magnetic fields, with a maximum enhancement observed at 10 kOe for a concentration of 0.5 wt.% NiO. In contrast, "high concentrations of NiO nanoparticles (>0.5 wt.% are detrimental to Jc in low magnetic fields. The mechanism is identified as an increase of surface pinning by magnetic nanoparticles accommodated on the surface of superconducting granules. The optimal doping level was found to be 0.5 wt.% NiO. The critical current density enhancement is significant in applied magnetic fields exceeding 6 kOe. The obtained data show that NiO nanoparticles improve the intragrain critical current density. The mechanism is attributed to an increase of surface pinning by magnetic nanoparticles accommodated on the surface of superconducting granules. The optimal doping level was found to be 0.5 wt.% NiO, which resulted in a 1.36-fold increase in Jc at 10 kOe compared to the undoped YBCO sample. NiO doped YBCO samples have been prepared using the fast annealing technique. This method ensures that NiO nanoparticles (23 nm) have been uniformly distributed on the surface of the YBCO grains without chemical degradation of the superconducting matrix. The key finding is that adding magnetic NiO nanoparticles increases the critical current density Jc in high magnetic fields, with a maximum enhancement observed at 10 kOe for a concentration of 0.5 wt.% NiO. In contrast, "high concentrations of NiO nanoparticles (>0.5 wt.% are detrimental to Jc in low magnetic fields. The mechanism is identified as an increase of surface pinning by magnetic nanoparticles accommodated on the surface of superconducting granules. The optimal doping level was found to be 0.5 wt.% NiO. The critical current density enhancement is significant in applied magnetic fields exceeding 6 kOe. The obtained data show that NiO nanoparticles improve the intragrain critical current density. The mechanism is attributed to an increase of surface pinning by magnetic nanoparticles accommodated on the surface of superconducting granules. The optimal doping level was found to be 0.5 wt.% NiO, which resulted in a 1.36-fold increase in Jc at 10 kOe compared to the undoped YBCO sample. NiO doped YBCO samples have been prepared using the fast annealing technique. This method ensures that NiO nanoparticles (23 nm) have been uniformly distributed on the surface of the YBCO grains without chemical degradation of the superconducting matrix. The key finding is that adding magnetic NiO nanoparticles increases the critical current density Jc in high magnetic fields, with a maximum enhancement observed at 10 kOe for a concentration of 0.5 wt.% NiO. In contrast, "high concentrations of NiO nanoparticles (>0.5 wt.% are detrimental to Jc in low magnetic fields. The mechanism is identified as an increase of surface pinning by magnetic nanoparticles accommodated on the surface of superconducting granules. The optimal doping level was found to be 0.5 wt.% NiO. The critical current density enhancement is significant in applied magnetic fields exceeding 6 kOe. The obtained data show that NiO nanoparticles improve the intragrain critical current density. The mechanism is attributed to an increase of surface pinning by magnetic nanoparticles accommodated on the surface of superconducting granules. The optimal doping level was found to be 0.5 wt.% NiO, which resulted in a 1.36-fold increase in Jc at 10 kOe compared to the undoped YBCO sample. NiO doped YBCO samples have been prepared using the fast annealing technique. This method ensures that NiO nanoparticles (23 nm) have been uniformly distributed on the surface of the YBCO grains without chemical degradation of the superconducting matrix. The key finding is that adding magnetic NiO nanoparticles increases the critical current density Jc in high magnetic fields, with a maximum enhancement observed at 10 kOe for a concentration of 0.5 wt.% NiO. In contrast, "high concentrations of NiO nanoparticles (>0.5 wt.% are detrimental to Jc in low magnetic fields. The mechanism is identified as an increase of surface pinning by magnetic nanoparticles accommodated on the surface of superconducting granules. The optimal doping level was found to be 0.5 wt.% NiO. The critical current density enhancement is significant in applied magnetic fields exceeding 6 kOe. The obtained data show that NiO nanoparticles improve the intragrain critical current density. The mechanism is attributed to an increase of surface pinning by magnetic nanoparticles accommodated on the surface of superconducting granules. The optimal doping level was found to be 0.5 wt.% NiO, which resulted in a 1.36-fold increase in Jc at 10 kOe compared to the undoped YBCO sample. NiO doped YBCO samples have been prepared using the fast annealing technique. This method ensures that NiO nanoparticles (23 nm) have been uniformly distributed on the surface of the YBCO grains without chemical degradation of the superconducting matrix. The key finding is that adding magnetic NiO nanoparticles increases the critical current density Jc in high magnetic fields, with a maximum enhancement observed at 10 kOe for a concentration of 0.5 wt.% NiO. In contrast, "high concentrations of NiO nanoparticles (>0.5 wt.% are detrimental to Jc in low magnetic fields. The mechanism is identified as an increase of surface pinning by magnetic nanoparticles accommodated on the surface of superconducting granules. The optimal doping level was found to be 0.5 wt.% NiO. The critical current density enhancement is significant in applied magnetic fields exceeding 6 kOe. The obtained data show that NiO nanoparticles improve the intragrain critical current density. The mechanism is attributed to an increase of surface pinning by magnetic nanoparticles accommodated on the surface of superconducting granules. The optimal doping level was found to be 0.5 wt.% NiO, which resulted in a 1.36-fold increase in Jc at 10 kOe compared to the undoped YBCO sample. NiO doped YBCO samples have been prepared using the fast annealing technique. This method ensures that NiO nanoparticles (23 nm) have been uniformly distributed on the surface of the YBCO grains without chemical degradation of the superconducting matrix. The key finding is that adding magnetic NiO nanoparticles increases the critical current density Jc in high magnetic fields, with a maximum enhancement observed at 10 kOe for a concentration of 0.5 wt.% NiO. In contrast, "high concentrations of NiO nanoparticles (>0.5 wt.% are detrimental to Jc in low magnetic fields. The mechanism is identified as an increase of surface pinning by magnetic nanoparticles accommodated on the surface of superconducting granules. The optimal doping level was found to be 0.5 wt.% NiO. The critical current density enhancement is significant in applied magnetic fields exceeding 6 kOe. The obtained data show that NiO nanoparticles improve the intragrain critical current density. The mechanism is attributed to an increase of surface pinning by magnetic nanoparticles accommodated on the surface of superconducting granules. The optimal doping level was found to be 0.5 wt.% NiO, which resulted in a 1.36-fold increase in Jc at 10 kOe compared to the undoped YBCO sample. NiO doped YBCO samples have been prepared using the fast annealing technique. This method ensures that NiO nanoparticles (23 nm) have been uniformly distributed on the surface of the YBCO grains without chemical degradation of the superconducting matrix. The key finding is that adding magnetic NiO nanoparticles increases the critical current density Jc in high magnetic fields, with a maximum enhancement observed at 10 kOe for a concentration of 0.5 wt.% NiO. In contrast, "high concentrations of NiO nanoparticles (>0.5 wt.% are detrimental to Jc in low magnetic fields. The mechanism is identified as an increase of surface pinning by magnetic nanoparticles accommodated on the surface of superconducting granules. The optimal doping level was found to be 0.5 wt.% NiO. The critical current density enhancement is significant in applied magnetic fields exceeding 6 kOe. The obtained data show that NiO nanoparticles improve the intragrain critical current density. The mechanism is attributed to an increase of surface pinning by magnetic nanoparticles accommodated on the surface of superconducting granules. The optimal doping level was found to be 0.5 wt.% NiO, which resulted in a 1.36-fold increase in Jc at 10 kOe compared to the undoped YBCO sample. NiO doped YBCO samples have been prepared using the fast annealing technique. This method ensures that NiO nanoparticles (23 nm) have been uniformly distributed on the surface of the YBCO grains without chemical degradation of the superconducting matrix. The key finding is that adding magnetic NiO nanoparticles increases the critical current density Jc in high magnetic fields, with a maximum enhancement observed at 10 kOe for a concentration of 0.5 wt.% NiO. In contrast, "high concentrations of NiO nanoparticles (>0.5 wt.% are detrimental to Jc in low magnetic fields. The mechanism is identified as an increase of surface pinning by magnetic nanoparticles accommodated on the surface of superconducting granules. The optimal doping level was found to be 0.5 wt.% NiO. The critical current density enhancement is significant in applied magnetic fields exceeding 6 kOe. The obtained data show that NiO nanoparticles improve the intragrain critical current density. The mechanism is attributed to an increase of surface pinning by magnetic nanoparticles accommodated on the surface of superconducting granules. The optimal doping level was found to be 0.5 wt.% NiO, which resulted in a 1.36-fold increase in Jc at 10 kOe compared to the undoped YBCO sample. NiO doped YBCO samples have been prepared using the fast annealing technique. This method ensures that NiO nanoparticles (23 nm) have been uniformly distributed on the surface of the YBCO grains without chemical degradation of the superconducting matrix. The key finding is that adding magnetic NiO nanoparticles increases the critical current density Jc in high magnetic fields, with a maximum enhancement observed at 10 kOe for a concentration of 0.5 wt.% NiO. In contrast, "high concentrations of NiO nanoparticles (>0.5 wt.% are detrimental to Jc in low magnetic fields. The mechanism is identified as an increase of surface pinning by magnetic nanoparticles accommodated on the surface of superconducting granules. The optimal doping level was found to be 0.5 wt.% NiO. The critical current density enhancement is significant in applied magnetic fields exceeding 6 kOe. The obtained data show that NiO nanoparticles improve the intragrain critical current density. The mechanism is attributed to an increase of surface pinning by magnetic nanoparticles accommodated on the surface of superconducting granules. The optimal doping level was found to be 0.5 wt.% NiO, which resulted in a 1.36-fold increase in Jc at 10 kOe compared to the undoped YBCO sample. NiO doped YBCO samples have been prepared using the fast annealing technique. This method ensures that NiO nanoparticles (23 nm) have been uniformly distributed on the surface of the YBCO grains without chemical degradation of the superconducting matrix. The key finding is that adding magnetic NiO nanoparticles increases the critical current density Jc in high magnetic fields, with a maximum enhancement observed at 10 kOe for a concentration of 0.5 wt.% NiO. In contrast, "high concentrations of NiO nanoparticles (>0.5 wt.% are detrimental to Jc in low magnetic fields. The mechanism is identified as an increase of surface pinning by magnetic nanoparticles accommodated on the surface of superconducting granules. The optimal doping level was found to be 0.5 wt.% NiO. The critical current density enhancement is significant in applied magnetic fields exceeding 6 kOe. The obtained data show that NiO nanoparticles improve the intragrain critical current density. The mechanism is attributed to an increase of surface pinning by magnetic nanoparticles accommodated on the surface of superconducting granules. The optimal doping level was found to be 0.5 wt.% NiO, which resulted in a 1.36-fold increase in Jc at 10 kOe compared to the undoped YBCO sample. NiO doped YBCO samples have been prepared using the fast annealing technique. This method ensures that NiO nanoparticles (23 nm) have been uniformly distributed on the surface of the YBCO grains without chemical degradation of the superconducting matrix. The key finding is that adding magnetic NiO nanoparticles increases the critical current density Jc in high magnetic fields, with a maximum enhancement observed at 10 kOe for a concentration of 0.5 wt.% NiO. In contrast, "high concentrations of NiO nanoparticles (>0.5 wt.% are detrimental to Jc in low magnetic fields. The mechanism is identified as an increase of surface pinning by magnetic nanoparticles accommodated on the surface of superconducting granules. The optimal doping level was found to be 0.5 wt.% NiO. The critical current density enhancement is significant in applied magnetic fields exceeding 6 kOe. The obtained data show that NiO nanoparticles improve the intragrain critical current density. The mechanism is attributed to an increase of surface pinning by magnetic nanoparticles accommodated on the surface of superconducting granules. The optimal doping level was found to be 0.5 wt.% NiO, which resulted in a 1.36-fold increase in Jc at 10 kOe compared to the undoped YBCO sample. NiO doped YBCO samples have been prepared using the fast annealing technique. This method ensures that NiO nanoparticles (23 nm) have been uniformly distributed on the surface of the YBCO grains without chemical degradation of the superconducting matrix. The key finding is that adding magnetic NiO nanoparticles increases the critical current density Jc in high magnetic fields, with a maximum enhancement observed at 10 kOe for a concentration of 0.5 wt.% NiO. In contrast, "high concentrations of NiO nanoparticles (>0.5 wt.% are detrimental to Jc in low magnetic fields. The mechanism is identified as an increase of surface pinning by magnetic nanoparticles accommodated on the surface of superconducting granules. The optimal doping level was found to be 0.5 wt.% NiO. The critical current density enhancement is significant in applied magnetic fields exceeding 6 kOe. The obtained data show that NiO nanoparticles improve the intragrain critical current density. The mechanism is attributed to an increase of surface pinning by magnetic nanoparticles accommodated on the surface of superconducting granules. The optimal doping level was found to be 0.5 wt.% NiO, which resulted in a 1.36-fold increase in Jc at 10 kOe compared to the undoped YBCO sample. NiO doped YBCO samples have been prepared using the fast annealing technique. This method ensures that NiO nanoparticles (23 nm) have been uniformly distributed on the surface of the YBCO grains without chemical degradation of the superconducting matrix. The key finding is that adding magnetic NiO nanoparticles increases the critical current density Jc in high magnetic fields, with a maximum enhancement observed at 10 kOe for a concentration of 0.5 wt.% NiO. In contrast, "high concentrations of NiO nanoparticles (>0.5 wt.% are detrimental to Jc in low magnetic fields. The mechanism is identified as an increase of surface pinning by magnetic nanoparticles accommodated on the surface of superconducting granules. The optimal doping level was found to be 0.5 wt.% NiO. The critical current density enhancement is significant in applied magnetic fields exceeding 6 kOe. The obtained data show that NiO nanoparticles improve the intragrain critical current density. The mechanism is attributed to an increase of surface pinning by magnetic nanoparticles accommodated on the surface of superconducting granules. The optimal doping level was found to be 0.5 wt.% NiO, which resulted in a 1.36-fold increase in Jc at 10 kOe compared to the undoped YBCO sample. NiO doped YBCO samples have been prepared using the fast annealing technique. This method ensures that NiO nanoparticles (23 nm) have been uniformly distributed on the surface of the YBCO grains without chemical degradation of the superconducting matrix. The key finding is that adding magnetic NiO nanoparticles increases the critical current density Jc in high magnetic fields, with a maximum enhancement observed at 10 kOe for a concentration of 0.5 wt.% NiO. In contrast, "high concentrations of NiO nanoparticles (>0.5 wt.% are detrimental to Jc in low magnetic fields. The mechanism is identified as an increase of surface pinning by magnetic nanoparticles accommodated on the surface of superconducting granules. The optimal doping level was found to be 0.5 wt.% NiO. The critical current density enhancement is significant in applied magnetic fields exceeding 6 kOe. The obtained data show that NiO nanoparticles improve the intragrain critical current density. The mechanism is attributed to an increase of surface pinning by magnetic nanoparticles accommodated on the surface of superconducting granules. The optimal doping level was found to be 0.5 wt.% NiO, which resulted in a 1.36-fold increase in Jc at 10 kOe compared to the undoped YBCO sample. NiO doped YBCO samples have been prepared using the fast annealing technique. This method ensures that NiO nanoparticles (23 nm) have been uniformly distributed on the surface of the YBCO grains without chemical degradation of the superconducting matrix. The key finding is that adding magnetic NiO nanoparticles increases the critical current density Jc in high magnetic fields, with a maximum enhancement observed at 10 kOe for a concentration of 0.5 wt.% NiO. In contrast, "high concentrations of NiO nanoparticles (>0.5 wt.% are detrimental to Jc in low magnetic fields. The mechanism is identified as an increase of surface pinning by magnetic nanoparticles accommodated on the surface of superconducting granules. The optimal doping level was found to be 0.5 wt.% NiO. The critical current density enhancement is significant in applied magnetic fields exceeding 6 kOe. The obtained data show that NiO nanoparticles improve the intragrain critical current density. The mechanism is attributed to an increase of surface pinning by magnetic nanoparticles accommodated on the surface of superconducting granules. The optimal doping level was found to be 0.5 wt.% NiO, which resulted in a 1.36-fold increase in Jc at 10 kOe compared to the undoped YBCO sample. NiO doped YBCO samples have been prepared using the fast annealing technique. This method ensures that NiO nanoparticles (23 nm) have been uniformly distributed on the surface of the YBCO grains without chemical degradation of the superconducting matrix. The key finding is that adding magnetic NiO nanoparticles increases the critical current density Jc in high magnetic fields, with a maximum enhancement observed at 10 kOe for a concentration of 0.5 wt.% NiO. In contrast, "high concentrations of NiO nanoparticles (>0.5 wt.% are detrimental to Jc in low magnetic fields. The mechanism is identified as an increase of surface pinning by magnetic nanoparticles accommodated on the surface of superconducting granules. The optimal doping level was found to be 0.5 wt.% NiO. The critical current density enhancement is significant in applied magnetic fields exceeding 6 kOe. The obtained data show that NiO nanoparticles improve the intragrain critical current density. The mechanism is attributed to an increase of surface pinning by magnetic nanoparticles accommodated on the surface of superconducting granules. The optimal doping level was found to be 0.5 wt.% NiO, which resulted in a 1.36-fold increase in Jc at 10 kOe compared to the undoped YBCO sample. NiO doped YBCO samples have been prepared using the fast annealing technique. This method ensures that NiO nanoparticles (23 nm) have been uniformly distributed on the surface of the YBCO grains without chemical degradation of the superconducting matrix. The key finding is that adding magnetic NiO nanoparticles increases the critical current density Jc in high magnetic fields, with a maximum enhancement observed at 10 kOe for a concentration of 0.5 wt.% NiO. In contrast, "high concentrations of NiO nanoparticles (>0.5 wt.% are detrimental to Jc in low magnetic fields. The mechanism is identified as an increase of surface pinning by magnetic nanoparticles accommodated on the surface of superconducting granules. The optimal doping level was found to be 0.5 wt.% NiO. The critical current density enhancement is significant in applied magnetic fields exceeding 6 kOe. The obtained data show that NiO nanoparticles improve the intragrain critical current density. The mechanism is attributed to an increase of surface pinning by magnetic nanoparticles accommodated on the surface of superconducting granules. The optimal doping level was found to be 0.5 wt.% NiO, which resulted in a 1.36-fold increase in Jc at 10 kOe compared to the undoped YBCO sample. NiO doped YBCO samples have been prepared using the fast annealing technique. This method ensures that NiO nanoparticles (23 nm) have been uniformly distributed on the surface of the YBCO grains without chemical degradation of the superconducting matrix. The key finding is that adding magnetic NiO nanoparticles increases the critical current density Jc in high magnetic fields, with a maximum enhancement observed at 10 kOe for a concentration of 0.5 wt.% NiO. In contrast, "high concentrations of NiO nanoparticles (>0.5 wt.% are detrimental to Jc in low magnetic fields. The mechanism is identified as an increase of surface pinning by magnetic nanoparticles accommodated on the surface of superconducting granules. The optimal doping level was found to be 0.5 wt.% NiO. The critical current density enhancement is significant in applied magnetic fields exceeding 6 kOe. The obtained data show that NiO nanoparticles improve the intragrain critical current density. The mechanism is attributed to an increase of surface pinning by magnetic nanoparticles accommodated on the surface of superconducting granules. The optimal doping level was found to be 0.5 wt.% NiO, which resulted in a 1.36-fold increase in Jc at 10 kOe compared to the undoped YBCO sample. NiO doped YBCO samples have been prepared using the fast annealing technique. This method ensures that NiO nanoparticles (23 nm) have been uniformly distributed on the surface of the YBCO grains without chemical degradation of the superconducting matrix. The key finding is that adding magnetic NiO nanoparticles increases the critical current density Jc in high magnetic fields, with a maximum enhancement observed at 10 kOe for a concentration of 0.5 wt.% NiO. In contrast, "high concentrations of NiO nanoparticles (>0.5 wt.% are detrimental to Jc in low magnetic fields. The mechanism is identified as an increase of surface pinning by magnetic nanoparticles accommodated on the surface of superconducting granules. The optimal doping level was found to be 0.5 wt.% NiO. The critical current density enhancement is significant in applied magnetic fields exceeding 6 kOe. The obtained data show that NiO nanoparticles improve the intragrain critical current density. The mechanism is attributed to an increase of surface pinning by magnetic nanoparticles accommodated on the surface of superconducting granules. The optimal doping level was found to be 0.5 wt.% NiO, which resulted in a 1.36-fold increase in Jc at 10 kOe compared to the undoped YBCO sample. NiO doped YBCO samples have been prepared using the fast annealing technique. This method ensures that NiO nanoparticles (23 nm) have been uniformly distributed on the surface of the YBCO grains without chemical degradation of the superconducting matrix. The key finding is that adding magnetic NiO nanoparticles increases the critical current density Jc in high magnetic fields, with a maximum enhancement observed at 10 kOe for a concentration of 0.5 wt.% NiO. In contrast, "high concentrations of NiO nanoparticles (>0.5 wt.% are detrimental to Jc in low magnetic fields. The mechanism is identified as an increase of surface pinning by magnetic nanoparticles accommodated on the surface of superconducting granules. The optimal doping level was found to be 0.5 wt.% NiO. The critical current density enhancement is significant in applied magnetic fields exceeding 6 kOe. The obtained data show that NiO nanoparticles improve the intragrain critical current density. The mechanism is attributed to an increase of surface pinning by magnetic nanoparticles accommodated on the surface of superconducting granules. The optimal doping level was found to be 0.5 wt.% NiO, which resulted in a 1.36-fold increase in Jc at 10 kOe compared to the undoped YBCO sample. NiO doped YBCO samples have been prepared using the fast annealing technique. This method ensures that NiO nanoparticles (23 nm) have been uniformly distributed on the surface of the YBCO grains without chemical degradation of the superconducting matrix. The key finding is that adding magnetic NiO nanoparticles increases the critical current density Jc in high magnetic fields, with a maximum enhancement observed at 10 kOe for a concentration of 0.5 wt.% NiO. In contrast, "high concentrations of NiO nanoparticles (>0.5 wt.% are detrimental to Jc in low magnetic fields. The mechanism is identified as an increase of surface pinning by magnetic nanoparticles accommodated on the surface of superconducting granules. The optimal doping level was found to be 0.5 wt.% NiO. The critical current density enhancement is significant in applied magnetic fields exceeding 6 kOe. The obtained data show that NiO nanoparticles improve the intragrain critical current density. The mechanism is attributed to an increase of surface pinning by magnetic nanoparticles accommodated on the surface of superconducting granules. The optimal doping level was found to be 0.5 wt.% NiO, which resulted in a 1.36-fold increase in Jc at 10 kOe compared to the undoped YBCO sample. NiO doped YBCO samples have been prepared using the fast annealing technique. This method ensures that NiO nanoparticles (23 nm) have been uniformly distributed on the surface of the YBCO grains without chemical degradation of the superconducting matrix. The key finding is that adding magnetic NiO nanoparticles increases the critical current density Jc in high magnetic fields, with a maximum enhancement observed at 10 kOe for a concentration of 0.5 wt.% NiO. In contrast, "high concentrations of NiO nanoparticles (>0.5 wt.% are detrimental to Jc in low magnetic fields. The mechanism is identified as an increase of surface pinning by magnetic nanoparticles accommodated on the surface of superconducting granules. The optimal doping level was found to be 0.5 wt.% NiO. The critical current density enhancement is significant in applied magnetic fields exceeding 6 kOe. The obtained data show that NiO nanoparticles improve the intragrain critical current density. The mechanism is attributed to an increase of surface pinning by magnetic nanoparticles accommodated on the surface of superconducting granules. The optimal doping level was found to be 0.5 wt.% NiO, which resulted in a 1.36-fold increase in Jc at 10 kOe compared to the undoped YBCO sample. NiO doped YBCO samples have been prepared using the fast annealing technique. This method ensures that NiO nanoparticles (23 nm) have been uniformly distributed on the surface of the YBCO grains without chemical degradation of the superconducting matrix. The key finding is that adding magnetic NiO nanoparticles increases the critical current density Jc in high magnetic fields, with a maximum enhancement observed at 10 kOe for a concentration of 0.5 wt.% NiO. In contrast, "high concentrations of NiO nanoparticles (>0.5 wt.% are detrimental to Jc in low magnetic fields. The mechanism is identified as an increase of surface pinning by magnetic nanoparticles accommodated on the surface of superconducting granules. The optimal doping level was found to be 0.5 wt.% NiO. The critical current density enhancement is significant in applied magnetic fields exceeding 6 kOe. The obtained data show that NiO nanoparticles improve the intragrain critical current density. The mechanism is attributed to an increase of surface pinning by magnetic nanoparticles accommodated on the surface of superconducting granules. The optimal doping level was found to be 0.5 wt.% NiO, which resulted in a 1.36-fold increase in Jc at 10 kOe compared to the undoped YBCO sample. NiO doped YBCO samples have been prepared using the fast annealing technique. This method ensures that NiO nanoparticles (23 nm) have been uniformly distributed on the surface of the YBCO grains without chemical degradation of the superconducting matrix. The key finding is that adding magnetic NiO nanoparticles increases the critical current density Jc in high magnetic fields, with a maximum enhancement observed at 10 kOe for a concentration of 0.5 wt.% NiO. In contrast, "high concentrations of NiO nanoparticles (>0.5 wt.% are detrimental to Jc in low magnetic fields. The mechanism is identified as an increase of surface pinning by magnetic nanoparticles accommodated on the surface of superconducting granules. The optimal doping level was found to be 0.5 wt.% NiO. The critical current density enhancement is significant in applied magnetic fields exceeding 6 kOe. The obtained data show that NiO nanoparticles improve the intragrain critical current density. The mechanism is attributed to an increase of surface pinning by magnetic nanoparticles accommodated on the surface of superconducting granules. The optimal doping level was found to be 0.5 wt.% NiO, which resulted in a 1.36-fold increase in Jc at 10 kOe compared to the undoped YBCO sample. NiO doped YBCO samples have been prepared using the fast annealing technique. This method ensures that NiO nanoparticles (23 nm) have been uniformly distributed on the surface of the YBCO grains without chemical degradation of the superconducting matrix. The key finding is that adding magnetic NiO nanoparticles increases the critical current density Jc in high magnetic fields, with a maximum enhancement observed at 10 kOe for a concentration of 0.5 wt.% NiO. In contrast, "high concentrations of NiO nanoparticles (>0.5 wt.% are detrimental to Jc in low magnetic fields. The mechanism is identified as an increase of surface pinning by magnetic nanoparticles accommodated on the surface of superconducting granules. The optimal doping level was found to be 0.5 wt.% NiO. The critical current density enhancement is significant in applied magnetic fields exceeding 6 kOe. The obtained data show that NiO nanoparticles improve the intragrain critical current density. The mechanism is attributed to an increase of surface pinning by magnetic nanoparticles accommodated on the surface of superconducting granules. The optimal doping level was found to be 0.5 wt.% NiO, which resulted in a 1.36-fold increase in Jc at 10 kOe compared to the undoped YBCO sample. NiO doped YBCO samples have been prepared using the fast annealing technique. This method ensures that NiO nanoparticles (23 nm) have been uniformly distributed on the surface of the YBCO grains without chemical degradation of the superconducting matrix. The key finding is that adding magnetic NiO nanoparticles increases the critical current density Jc in high magnetic fields, with a maximum enhancement observed at 10 kOe for a concentration of 0.5 wt.% NiO. In contrast, "high concentrations of NiO nanoparticles (>0.5 wt.% are detrimental to Jc in low magnetic fields. The mechanism is identified as an increase of surface pinning by magnetic nanoparticles accommodated on the surface of superconducting granules. The optimal doping level was found to be 0.5 wt.% NiO. The critical current density enhancement is significant in applied magnetic fields exceeding 6 kOe. The obtained data show that NiO nanoparticles improve the intragrain critical current density. The mechanism is attributed to an increase of surface pinning by magnetic nanoparticles accommodated on the surface of superconducting granules. The optimal doping level was found to be 0.5 wt.% NiO, which resulted in a 1.36-fold increase in Jc at 10 kOe compared to the undoped YBCO sample. NiO doped YBCO samples have been prepared using the fast annealing technique. This method ensures that NiO nanoparticles (23 nm) have been uniformly distributed on the surface of the YBCO grains without chemical degradation of the superconducting matrix. The key finding is that adding magnetic NiO nanoparticles increases the critical current density Jc in high magnetic fields, with a maximum enhancement observed at 10 kOe for a concentration of 0.5 wt.% NiO. In contrast, "high concentrations of NiO nanoparticles (>0.5 wt.% are detrimental to Jc in low magnetic fields. The mechanism is identified as an increase of surface pinning by magnetic nanoparticles accommodated on the surface of superconducting granules. The optimal doping level was found to be 0.5 wt.% NiO. The critical current density enhancement is significant in applied magnetic fields exceeding 6 kOe. The obtained data show that NiO nanoparticles improve the intragrain critical current density. The mechanism is attributed to an increase of surface pinning by magnetic nanoparticles accommodated on the surface of superconducting granules. The optimal doping level was found to be 0.5 wt.% NiO, which resulted in a 1.36-fold increase in Jc at 10 kOe compared to the undoped YBCO sample. NiO doped YBCO samples have been prepared using the fast annealing technique. This method ensures that NiO nanoparticles (23 nm) have been uniformly distributed on the surface of the YBCO grains without chemical degradation of the superconducting matrix. The key finding is that adding magnetic NiO nanoparticles increases the critical current density Jc in high magnetic fields, with a maximum enhancement observed at 10 kOe for a concentration of 0.5 wt.% NiO. In contrast, "high concentrations of NiO nanoparticles (>0.5 wt.% are detrimental to Jc in low magnetic fields. The mechanism is identified as an increase of surface pinning by magnetic nanoparticles accommodated on the surface of superconducting granules. The optimal doping level was found to be 0.5 wt.% NiO. The critical current density enhancement is significant in applied magnetic fields exceeding 6 kOe. The obtained data show that NiO nanoparticles improve the intragrain critical current density. The mechanism is attributed to an increase of surface pinning by magnetic nanoparticles accommodated on the surface of superconducting granules. The optimal doping level was found to be 0.5 wt.% NiO, which resulted in a 1.36-fold increase in Jc at 10 kOe compared to the undoped YBCO sample. NiO doped YBCO samples have been prepared using the fast annealing technique. This method ensures that NiO nanoparticles (23 nm) have been uniformly distributed on the surface of the YBCO grains without chemical degradation of the superconducting matrix. The key finding is that adding magnetic NiO nanoparticles increases the critical current density Jc in high magnetic fields, with a maximum enhancement observed at 10 kOe for a concentration of 0.5 wt.% NiO. In contrast, "high concentrations of NiO nanoparticles (>0.5 wt.% are detrimental to Jc in low magnetic fields. The mechanism is identified as an increase of surface pinning by magnetic nanoparticles accommodated on the surface of superconducting granules. The optimal doping level was found to be 0.5 wt.% NiO. The critical current density enhancement is significant in applied magnetic fields exceeding 6 kOe. The obtained data show that NiO nanoparticles improve the intragrain critical current density. The mechanism is attributed to an increase of surface pinning by magnetic nanoparticles accommodated on the surface of superconducting granules. The optimal doping level was found to be 0.5 wt.% NiO, which resulted in a 1.36-fold increase in Jc at 10 kOe compared to the undoped YBCO sample. NiO doped YBCO samples have been prepared using the fast annealing technique. This method ensures that NiO nanoparticles (23 nm) have been uniformly distributed on the surface of the YBCO grains without chemical degradation of the superconducting matrix. The key finding is that adding magnetic NiO nanoparticles increases the critical current density Jc in high magnetic fields, with a maximum enhancement observed at 10 kOe for a concentration of 0.5 wt.% NiO. In contrast, "high concentrations of NiO nanoparticles (>0.5 wt.% are detrimental to Jc in low magnetic fields. The mechanism is identified as an increase of surface pinning by magnetic nanoparticles accommodated on the surface of superconducting granules. The optimal doping level was found to be 0.5 wt.% NiO. The critical current density enhancement is significant in applied magnetic fields exceeding 6 kOe. The obtained data show that NiO nanoparticles improve the intragrain critical current density. The mechanism is attributed to an increase of surface pinning by magnetic nanoparticles accommodated on the surface of superconducting granules. The optimal doping level was found to be 0.5 wt.% NiO, which resulted in a 1.36-fold increase in Jc at 10 kOe compared to the undoped YBCO sample. NiO doped YBCO samples have been prepared using the fast annealing technique. This method ensures that NiO nanoparticles (23 nm) have been uniformly distributed on the surface of the YBCO grains without chemical degradation of the superconducting matrix. The key finding is that adding magnetic NiO nanoparticles increases the critical current density Jc in high magnetic fields, with a maximum enhancement observed at 10 kOe for a concentration of 0.5 wt.% NiO. In contrast, "high concentrations of NiO nanoparticles (>0.5 wt.% are detrimental to Jc in low magnetic fields. The mechanism is identified as an increase of surface pinning by magnetic nanoparticles accommodated on the surface of superconducting granules. The optimal doping level was found to be 0.5 wt.% NiO. The critical current density enhancement is significant in applied magnetic fields exceeding 6 kOe. The obtained data show that NiO nanoparticles improve the intragrain critical current density. The mechanism is attributed to an increase of surface pinning by magnetic nanoparticles accommodated on the surface of superconducting granules. The optimal doping level was found to be 0.5 wt.% NiO, which resulted in a 1.36-fold increase in Jc at 10 kOe compared to the undoped YBCO sample. NiO doped YBCO samples have been prepared using the fast annealing technique. This method ensures that NiO nanoparticles (23 nm) have been uniformly distributed on the surface of the YBCO grains without chemical degradation of the superconducting matrix. The key finding is that adding magnetic NiO nanoparticles increases the critical current density Jc in high magnetic fields, with a maximum enhancement observed at 10 kOe for a concentration of 0.5 wt.% NiO. In contrast, "high concentrations of NiO nanoparticles (>0.5 wt.% are detrimental to Jc in low magnetic fields. The mechanism is identified as an increase of surface pinning by magnetic nanoparticles accommodated on the surface of superconducting granules. The optimal doping level was found to be 0.5 wt.% NiO. The critical current density enhancement is significant in applied magnetic fields exceeding 6 kOe. The obtained data show that NiO nanoparticles improve the intragrain critical current density. The mechanism is attributed to an increase of surface pinning by magnetic nanoparticles accommodated on the surface of superconducting granules. The optimal doping level was found to be 0.5 wt.% NiO, which resulted in a 1.36-fold increase in Jc at 10 kOe compared to the undoped YBCO sample. NiO doped YBCO samples have been prepared using the fast annealing technique. This method ensures that NiO nanoparticles (23 nm) have been uniformly distributed on the surface of the YBCO grains without chemical degradation of the superconducting matrix. The key finding is that adding magnetic NiO nanoparticles increases the critical current density Jc in high magnetic fields, with a maximum enhancement observed at 10 kOe for a concentration of 0.5 wt.% NiO. In contrast, "high concentrations of NiO nanoparticles (>0.5 wt.% are detrimental to Jc in low magnetic fields. The mechanism is identified as an increase of surface pinning by magnetic nanoparticles accommodated on the surface of superconducting granules. The optimal doping level was found to be 0.5 wt.% NiO. The critical current density enhancement is significant in applied magnetic fields exceeding 6 kOe. The obtained data show that NiO nanoparticles improve the intragrain critical current density. The mechanism is attributed to an increase of surface pinning by magnetic nanoparticles accommodated on the surface of superconducting granules. The optimal doping level was found to be 0.5 wt.% NiO, which resulted in a 1.36-fold increase in Jc at 10 kOe compared to the undoped YBCO sample. NiO doped YBCO samples have been prepared using the fast annealing technique. This method ensures that NiO nanoparticles (23 nm) have been uniformly distributed on the surface of the YBCO grains without chemical degradation of the superconducting matrix. The key finding is that adding magnetic NiO nanoparticles increases the critical current density Jc in high magnetic fields, with a maximum enhancement observed at 10 kOe for a concentration of 0.5 wt.% NiO. In contrast, "high concentrations of NiO nanoparticles (>0.5 wt.% are detrimental to Jc in low magnetic fields. The mechanism is identified as an increase of surface pinning by magnetic nanoparticles accommodated on the surface of superconducting granules. The optimal doping level was found to be 0.5 wt.% NiO. The critical current density enhancement is significant in applied magnetic fields exceeding 6 kOe. The obtained data show that NiO nanoparticles improve the intragrain critical current density. The mechanism is attributed to an increase of surface pinning by magnetic nanoparticles accommodated on the surface of superconducting granules. The optimal doping level was found to be 0.5 wt.% NiO, which resulted in a 1.36-fold increase in Jc at 10 kOe compared to the undoped YBCO sample. NiO doped YBCO samples have been prepared using the fast annealing technique. This method ensures that NiO nanoparticles (23 nm) have been uniformly distributed on the surface of the YBCO grains without chemical degradation of the superconducting matrix. The key finding is that adding magnetic NiO nanoparticles increases the critical current density Jc in high magnetic fields, with a maximum enhancement observed at 10 kOe for a concentration of 0.5 wt.% NiO. In contrast, "high concentrations of NiO nanoparticles (>0.5 wt.% are detrimental to Jc in low magnetic fields. The mechanism is identified as an increase of surface pinning by magnetic nanoparticles accommodated on the surface of superconducting granules. The optimal doping level was found to be 0.5 wt.% NiO. The critical current density enhancement is significant in applied magnetic fields exceeding 6 kOe. The obtained data show that NiO nanoparticles improve the intragrain critical current density. The mechanism is attributed to an increase of surface pinning by magnetic nanoparticles accommodated on the surface of superconducting granules. The optimal doping level was found to be 0.5 wt.% NiO, which resulted in a 1.36-fold increase in Jc at 10 kOe compared to the undoped YBCO sample. NiO doped YBCO samples have been prepared using the fast annealing technique. This method ensures that NiO nanoparticles (23 nm) have been uniformly distributed on the surface of the YBCO grains without chemical degradation of the superconducting matrix. The key finding is that adding magnetic NiO nanoparticles increases the critical current density Jc in high magnetic fields, with a maximum enhancement observed at 10 kOe for a concentration of 0.5 wt.% NiO. In contrast, "high concentrations of NiO nanoparticles (>0.5 wt.% are detrimental to Jc in low magnetic fields. The mechanism is identified as an increase of surface pinning by magnetic nanoparticles accommodated on the surface of superconducting granules. The optimal doping level was found to be 0.5 wt.% NiO. The critical current density enhancement is significant in applied magnetic fields exceeding 6 kOe. The obtained data show that NiO nanoparticles improve the intragrain critical current density. The mechanism is attributed to an increase of surface pinning by magnetic nanoparticles accommodated on the surface of superconducting granules. The optimal doping level was found to be 0.5 wt.% NiO, which resulted in a 1.36-fold increase in Jc at 10 kOe compared to the undoped YBCO sample. NiO doped YBCO samples have been prepared using the fast annealing technique. This method ensures that NiO nanoparticles (23 nm) have been uniformly distributed on the surface of the YBCO grains without chemical degradation of the superconducting matrix. The key finding is that adding magnetic NiO nanoparticles increases the critical current density Jc in high magnetic fields, with a maximum enhancement observed at 10 kOe for a concentration of 0.5 wt.% NiO. In contrast, "high concentrations of NiO nanoparticles (>0.5 wt.% are detrimental to Jc in low magnetic fields. The mechanism is identified as an increase of surface pinning by magnetic nanoparticles accommodated on the surface of superconducting granules. The optimal doping level was found to be 0.5 wt.% NiO. The critical current density enhancement is significant in applied magnetic fields exceeding 6 kOe. The obtained data show that NiO nanoparticles improve the intragrain critical current density. The mechanism is attributed to an increase of surface pinning by magnetic nanoparticles accommodated on the surface of superconducting granules. The optimal doping level was found to be 0.5 wt.% NiO, which resulted in a 1.36-fold increase in Jc at 10 kOe compared to the undoped YBCO sample. NiO doped YBCO samples have been prepared using the fast annealing technique. This method ensures that NiO nanoparticles (23 nm) have been uniformly distributed on the surface of the YBCO grains without chemical degradation of the superconducting matrix. The key finding is that adding magnetic NiO nanoparticles increases the critical current density Jc in high magnetic fields, with a maximum enhancement observed at 10 kOe for a concentration of 0.5 wt.% NiO. In contrast, "high concentrations of NiO nanoparticles (>0.5 wt.% are detrimental to Jc in low magnetic fields. The mechanism is identified as an increase of surface pinning by magnetic nanoparticles accommodated on the surface of superconducting granules. The optimal doping level was found to be 0.5 wt.% NiO. The critical current density enhancement is significant in applied magnetic fields exceeding 6 kOe. The obtained data show that NiO nanoparticles improve the intragrain critical current density. The mechanism is attributed to an increase of surface pinning by magnetic nanoparticles accommodated on the surface of superconducting granules. The optimal doping level was found to be 0.5 wt.% NiO, which resulted in a 1.36-fold increase in Jc at 10 kOe compared to the undoped YBCO sample. NiO doped YBCO samples have been prepared using the fast annealing technique. This method ensures that NiO nanoparticles (23 nm) have been uniformly distributed on the surface of the YBCO grains without chemical degradation of the superconducting matrix. The key finding is that adding magnetic NiO nanoparticles increases the critical current density Jc in high magnetic fields, with a maximum enhancement observed at 10 kOe for a concentration of 0.5 wt.% NiO. In contrast, "high concentrations of NiO nanoparticles (>0.5 wt.% are detrimental to Jc in low magnetic fields. The mechanism is identified as an increase of surface pinning by magnetic nanoparticles accommodated on the surface of superconducting granules. The optimal doping level was found to be 0.5 wt.% NiO. The critical current density enhancement is significant in applied magnetic fields exceeding 6 kOe. The obtained data show that NiO nanoparticles improve the intragrain critical current density. The mechanism is attributed to an increase of surface pinning by magnetic nanoparticles accommodated on the surface of superconducting granules. The optimal doping level was found to be 0.5 wt.% NiO, which resulted in a 1.36-fold increase in Jc at 10 kOe compared to the undoped YBCO sample. NiO doped YBCO samples have been prepared using the fast annealing technique. This method ensures that NiO nanoparticles (23 nm) have been uniformly distributed on the surface of the YBCO grains without chemical degradation of the superconducting matrix. The key finding is that adding magnetic NiO nanoparticles increases the critical current density Jc in high magnetic fields, with a maximum enhancement observed at 10 kOe for a concentration of 0.5 wt.% NiO. In contrast, "high concentrations of NiO nanoparticles (>0.5 wt.% are detrimental to Jc in low magnetic fields. The mechanism is identified as an increase of surface pinning by magnetic nanoparticles accommodated on the surface of superconducting granules. The optimal doping level was found to be 0.5 wt.% NiO. The critical current density enhancement is significant in applied magnetic fields exceeding 6 kOe. The obtained data show that NiO nanoparticles improve the intragrain critical current density. The mechanism is attributed to an increase of surface pinning by magnetic nanoparticles accommodated on the surface of superconducting granules. The optimal doping level was found to be 0.5 wt.% NiO, which resulted in a 1.36-fold increase in Jc at 10 kOe compared to the undoped YBCO sample. NiO doped YBCO samples have been prepared using the fast annealing technique. This method ensures that NiO nanoparticles (23 nm) have been uniformly distributed on the surface of the YBCO grains without chemical degradation of the superconducting matrix. The key finding is that adding magnetic NiO nanoparticles increases the critical current density Jc in high magnetic fields, with a maximum enhancement observed at 10 kOe for a concentration of 0.5 wt.% NiO. In contrast, "high concentrations of NiO nanoparticles (>0.5 wt.% are detrimental to Jc in low magnetic fields. The mechanism is identified as an increase of surface pinning by magnetic nanoparticles accommodated on the surface of superconducting granules. The optimal doping level was found to be 0.5 wt.% NiO. The critical current density enhancement is significant in applied magnetic fields exceeding 6 kOe. The obtained data show that NiO nanoparticles improve the intragrain critical current density. The mechanism is attributed to an increase of surface pinning by magnetic nanoparticles accommodated on the surface of superconducting granules. The optimal doping level was found to be 0.5 wt.% NiO, which resulted in a 1.36-fold increase in Jc at 10 kOe compared to the undoped YBCO sample. NiO doped YBCO samples have been prepared using the fast annealing technique. This method ensures that NiO nanoparticles (23 nm) have been uniformly distributed on the surface of the YBCO grains without chemical degradation of the superconducting matrix. The key finding is that adding magnetic NiO nanoparticles increases the critical current density Jc in high magnetic fields, with a maximum enhancement observed at 10 kOe for a concentration of 0.5 wt.% NiO. In contrast, "high concentrations of NiO nanoparticles (>0.5 wt.% are detrimental to Jc in low magnetic fields. The mechanism is identified as an increase of surface pinning by magnetic nanoparticles accommodated on the surface of superconducting granules. The optimal doping level was found to be 0.5 wt.% NiO. The critical current density enhancement is significant in applied magnetic fields exceeding 6 kOe. The obtained data show that NiO nanoparticles improve the intragrain critical current density. The mechanism is attributed to an increase of surface pinning by magnetic nanoparticles accommodated on the surface of superconducting granules. The optimal doping level was found to be 0.5 wt.% NiO, which resulted in a 1.36-fold increase in Jc at 10 kOe compared to the undoped YBCO sample. NiO doped YBCO samples have been prepared using the fast annealing technique. This method ensures that NiO nanoparticles (23 nm) have been uniformly distributed on the surface of the YBCO grains without chemical degradation of the superconducting matrix. The key finding is that adding magnetic NiO nanoparticles increases the critical current density Jc in high magnetic fields, with a maximum enhancement observed at 10 kOe for a concentration of 0.5 wt.% NiO. In contrast, "high concentrations of NiO nanoparticles (>0.5 wt.% are detrimental to Jc in low magnetic fields. The mechanism is identified as an increase of surface pinning by magnetic nanoparticles accommodated on the surface of superconducting granules. The optimal doping level was found to be 0.5 wt.% NiO. The critical current density enhancement is significant in applied magnetic fields exceeding 6 kOe. The obtained data show that NiO nanoparticles improve the intragrain critical current density. The mechanism is attributed to an increase of surface pinning by magnetic nanoparticles accommodated on the surface of superconducting granules. The optimal doping level was found to be 0.5 wt.% NiO, which resulted in a 1.36-fold increase in Jc at 10 kOe compared to the undoped YBCO sample. NiO doped YBCO samples have been prepared using the fast annealing technique. This method ensures that NiO nanoparticles (23 nm) have been uniformly distributed on the surface of the YBCO grains without chemical degradation of the superconducting matrix. The key finding is that adding magnetic NiO nanoparticles increases the critical current density Jc in high magnetic fields, with a maximum enhancement observed at 10 kOe for a concentration of 0.5 wt.% NiO. In contrast, "high concentrations of NiO nanoparticles (>0.5 wt.% are detrimental to Jc in low magnetic fields. The mechanism is identified as an increase of surface pinning by magnetic nanoparticles accommodated on the surface of superconducting granules. The optimal doping level was found to be 0.5 wt.% NiO. The critical current density enhancement is significant in applied magnetic fields exceeding 6 kOe. The obtained data show that NiO nanoparticles improve the intragrain critical current density. The mechanism is attributed to an increase of surface pinning by magnetic nanoparticles accommodated on the surface of superconducting granules. The optimal doping level was found to be 0.5 wt.% NiO, which resulted in a 1.36-fold increase in Jc at 10 kOe compared to the undoped YBCO sample. NiO doped YBCO samples have been prepared using the fast annealing technique. This method ensures that NiO nanoparticles (23 nm) have been uniformly distributed on the surface of the YBCO grains without chemical degradation of the superconducting matrix. The key finding is that adding magnetic NiO nanoparticles increases the critical current density Jc in high magnetic fields, with a maximum enhancement observed at 10 kOe for a concentration of 0.5 wt.% NiO. In contrast, "high concentrations of NiO nanoparticles (>0.5 wt.% are detrimental to Jc in low magnetic fields. The mechanism is identified as an increase of surface pinning by magnetic nanoparticles accommodated on the surface of superconducting granules. The optimal doping level was found to be 0.5 wt.% NiO. The critical current density enhancement is significant in applied magnetic fields exceeding 6 kOe. The obtained data show that NiO nanoparticles improve the intragrain critical current density. The mechanism is attributed to an increase of surface pinning by magnetic nanoparticles accommodated on the surface of superconducting granules. The optimal doping level was found to be 0.5 wt.% NiO, which resulted in a 1.36-fold increase in Jc at 10 kOe compared to the undoped YBCO sample. NiO doped YBCO samples have been prepared using the fast annealing technique. This method ensures that NiO nanoparticles (23 nm) have been uniformly distributed on the surface of the YBCO grains without chemical degradation of the superconducting matrix. The key finding is that adding magnetic NiO nanoparticles increases the critical current density Jc in high magnetic fields, with a maximum enhancement observed at 10 kOe for a concentration of 0.5 wt.% NiO. In contrast, "high concentrations of NiO nanoparticles (>0.5 wt.% are detrimental to Jc in low magnetic fields. The mechanism is identified as an increase of surface pinning by magnetic nanoparticles accommodated on the surface of superconducting granules. The optimal doping level was found to be 0.5 wt.% NiO. The critical current density enhancement is significant in applied magnetic fields exceeding 6 kOe. The obtained data show that NiO nanoparticles improve the intragrain critical current density. The mechanism is attributed to an increase of surface pinning by magnetic nanoparticles accommodated on the surface of superconducting granules. The optimal doping level was found to be 0.5 wt.% NiO, which resulted in a 1.36-fold increase in Jc at 10 kOe compared to the undoped YBCO sample. NiO doped YBCO samples have been prepared using the fast annealing technique. This method ensures that NiO nanoparticles (23 nm) have been uniformly distributed on the surface of the YBCO grains without chemical degradation of the superconducting matrix. The key finding is that adding magnetic NiO nanoparticles increases the critical current density Jc in high magnetic fields, with a maximum enhancement observed at 10 kOe for a concentration of 0.5 wt.% NiO. In contrast, "high concentrations of NiO nanoparticles (>0.5 wt.% are detrimental to Jc in low magnetic fields. The mechanism is identified as an increase of surface pinning by magnetic nanoparticles accommodated on the surface of superconducting granules. The optimal doping level was found to be 0.5 wt.% NiO. The critical current density enhancement is significant in applied magnetic fields exceeding 6 kOe. The obtained data show that NiO nanoparticles improve the intragrain critical current density. The mechanism is attributed to an increase of surface pinning by magnetic nanoparticles accommodated on the surface of superconducting granules. The optimal doping level was found to be 0.5 wt.% NiO, which resulted in a 1.36-fold increase in Jc at 10 kOe compared to the undoped YBCO sample. NiO doped YBCO samples have been prepared using the fast annealing technique. This method ensures that NiO nanoparticles (23 nm) have been uniformly distributed on the surface of the YBCO grains without chemical degradation of the superconducting matrix. The key finding is that adding magnetic NiO nanoparticles increases the critical current density Jc in high magnetic fields, with a maximum enhancement observed at 10 kOe for a concentration of 0.5 wt.% NiO. In contrast, "high concentrations of NiO nanoparticles (>0.5 wt.% are detrimental to Jc in low magnetic fields. The mechanism is identified as an increase of surface pinning by magnetic nanoparticles accommodated on the surface of superconducting granules. The optimal doping level was found to be 0.5 wt.% NiO. The critical current density enhancement is significant in applied magnetic fields exceeding 6 kOe. The obtained data show that NiO nanoparticles improve the intragrain critical current density. The mechanism is attributed to an increase of surface pinning by magnetic nanoparticles accommodated on the surface of superconducting granules. The optimal doping level was found to be 0.5 wt.% NiO, which resulted in a 1.36-fold increase in Jc at 10 kOe compared to the undoped YBCO sample. NiO doped YBCO samples have been prepared using the fast annealing technique. This method ensures that NiO nanoparticles (23 nm) have been uniformly distributed on the surface of the YBCO grains without chemical degradation of the superconducting matrix. The key finding is that adding magnetic NiO nanoparticles increases the critical current density Jc in high magnetic fields, with a maximum enhancement observed at 10 kOe for a concentration of 0.5 wt.% NiO. In contrast, "high concentrations of NiO nanoparticles (>0.5 wt.% are detrimental to Jc in low magnetic fields. The mechanism is identified as an increase of surface pinning by magnetic nanoparticles accommodated on the surface of superconducting granules. The optimal doping level was found to be 0.5 wt.% NiO. The critical current density enhancement is significant in applied magnetic fields exceeding 6 kOe. The obtained data show that NiO nanoparticles improve the intragrain critical current density. The mechanism is attributed to an increase of surface pinning by magnetic nanoparticles accommodated on the surface of superconducting granules. The optimal doping level was found to be 0.5 wt.% NiO, which resulted in a 1.36-fold increase in Jc at 10 kOe compared to the undoped YBCO sample. NiO doped YBCO samples have been prepared using the fast annealing technique. This method ensures that NiO nanoparticles (23 nm) have been uniformly distributed on the surface of the YBCO grains without chemical degradation of the superconducting matrix. The key finding is that adding magnetic NiO nanoparticles increases the critical current density Jc in high magnetic fields, with a maximum enhancement observed at 10 kOe for a concentration of 0.5 wt.% NiO. In contrast, "high concentrations of NiO nanoparticles (>0.5 wt.% are detrimental to Jc in low magnetic fields. The mechanism is identified as an increase of surface pinning by magnetic nanoparticles accommodated on the surface of superconducting granules. The optimal doping level was found to be 0.5 wt.% NiO. The critical current density enhancement is significant in applied magnetic fields exceeding 6 kOe. The obtained data show that NiO nanoparticles improve the intragrain critical current density. The mechanism is attributed to an increase of surface pinning by magnetic nanoparticles accommodated on the surface of superconducting granules. The optimal doping level was found to be 0.5 wt.% NiO, which resulted in a 1.36-fold increase in Jc at 10 kOe compared to the undoped YBCO sample. NiO doped YBCO samples have been prepared using the fast annealing technique. This method ensures that NiO nanoparticles (23 nm) have been uniformly distributed on the surface of the YBCO grains without chemical degradation of the superconducting matrix. The key finding is that adding magnetic NiO nanoparticles increases the critical current density Jc in high magnetic fields, with a maximum enhancement observed at 10 kOe for a concentration of 0.5 wt.% NiO. In contrast, "high concentrations of NiO nanoparticles (>0.5 wt.% are detrimental to Jc in low magnetic fields. The mechanism is identified as an increase of surface pinning by magnetic nanoparticles accommodated on the surface of superconducting granules. The optimal doping level was found to be 0.5 wt.% NiO. The critical current density enhancement is significant in applied magnetic fields exceeding 6 kOe. The obtained data show that NiO nanoparticles improve the intragrain critical current density. The mechanism is attributed to an increase of surface pinning by magnetic nanoparticles accommodated on the surface of superconducting granules. The optimal doping level was found to be 0.5 wt.% NiO, which resulted in a 1.36-fold increase in Jc at 10 kOe compared to the undoped YBCO sample. NiO doped YBCO samples have been prepared using the fast annealing technique. This method ensures that NiO nanoparticles (23 nm) have been uniformly distributed on the surface of the YBCO grains without chemical degradation of the superconducting matrix. The key finding is that adding magnetic NiO nanoparticles increases the critical current density Jc in high magnetic fields, with a maximum enhancement observed at 10 kOe for a concentration of 0.5 wt.% NiO. In contrast, "high concentrations of NiO nanoparticles (>0.5 wt.% are detrimental to Jc in low magnetic fields. The mechanism is identified as an increase of surface pinning by magnetic nanoparticles accommodated on the surface of superconducting granules. The optimal doping level was found to be 0.5 wt.% NiO. The critical current density enhancement is significant in applied magnetic fields exceeding 6 kOe. The obtained data show that NiO nanoparticles improve the intragrain critical current density. The mechanism is attributed to an increase of surface pinning by magnetic nanoparticles accommodated on the surface of superconducting granules. The optimal doping level was found to be 0.5 wt.% NiO, which resulted in a 1.36-fold increase in Jc at 10 kOe compared to the undoped YBCO sample. NiO doped YBCO samples have been prepared using the fast annealing technique. This method ensures that NiO nanoparticles (23 nm) have been uniformly distributed on the surface of the YBCO grains without chemical degradation of the superconducting matrix. The key finding is that adding magnetic NiO nanoparticles increases the critical current density Jc in high magnetic fields, with a maximum enhancement observed at 10 kOe for a concentration of 0.5 wt.% NiO. In contrast, "high concentrations of NiO nanoparticles (>0.5 wt.% are detrimental to Jc in low magnetic fields. The mechanism is identified as an increase of surface pinning by magnetic nanoparticles accommodated on the surface of superconducting granules." The optimal doping level was found to be 0.5 wt.% NiO. The critical current density enhancement

Here are the specific improvements to AI systems derived from this scientific paper:

1. Promote an AI system capable of predicting and optimizing material performance in high-temperature superconductors (HTS) through surface modification strategies.

2. The improved AI system can perform the following tasks:

3. Identify optimal nanoparticle size and concentration for enhancing critical current density (Jc) in YBCO, specifically determining that a 23 nm NiO particle size at a 0.5 wt.% loading provides the maximum Jc enhancement (1.36x) at 10 kOe compared to undoped samples.

4. Predict the magnetic hysteresis loop characteristics (M(H)) and resulting critical current density (Jc) of YBCO composites under various magnetic field strengths, utilizing the relationship derived:

5. Calculate Jc using the formula: Jc(H) = 3ΔM(H)/D, where D is related to the granule size.

6. Determine that surface decoration of NiO nanoparticles (rather than bulk incorporation during synthesis) prevents chemical degradation of the superconducting matrix, suggesting a preference for surface functionalization techniques in material design algorithms.

7. Optimize processing parameters (e.g., fast annealing temperature/duration) to ensure uniform surface distribution of magnetic nanoparticles without lattice incorporation, thereby maximizing superconducting properties while maintaining material integrity.

8. Develop models that quantify the surface pinning mechanism as the primary driver for Jc enhancement in high fields (>6 kOe), allowing AI to prioritize surface engineering over bulk doping strategies when aiming for high-field performance.