A chemical avenue to manipulate field-reentrant superconducting rivalries in infinite layer nickelates

summary

Video file (mp4)

The gist

The gist: A chemical avenue to manipulate field-reentrant superconducting rivalries in infinite layer nickelates elucidates how RE-4f orbital and spin interplays modulate quantum phase criticality

In short

Researchers developed a chemical growth strategy using high-pO2 conditions to effectively grow infinite layer nickelates with various rare-earth elements (REs). This allowed them to study how RE-4f orbital and spin interactions modulate quantum phase criticality, leading to enhanced superconducting transition temperatures up to 40 K and robust critical currents of 266 kA/cm2.

Key concepts

Field-Reentrant Superconductivity
This phenomenon occurs when superconductivity appears again (re-enters) at the boundaries of the superconducting dome, even when high-temperature superconductivity is present. It is driven by a competition between magnetic fluctuations promoted pairing and exchange-field interactions, which are highly tunable by rare-earth elements.
Quantum Criticality Modulation
The critical point where quantum phase transitions occur can be adjusted by substituting rare-earth elements (RE1) with other REs (RE'). This substitution alters the internal exchange field associated with the magnetism, which in turn modifies how strongly magnetic fluctuations pair electrons and affects the overall superconducting properties.
Eu2+-4f7 Interaction
The Eu2+ ion, specifically its 4f7 configuration, plays a crucial role beyond simple doping. It contributes to both the exchange field and acts as a hole dopant. This dual role strengthens Cooper pairing through promoted magnetic fluctuations, leading to significantly higher superconducting transition temperatures compared to systems doped with Sr or Ca.
High-pO2 Chemical Growth Strategy
A specific chemical method was used involving dissolving precursors in EGME and using soft chemical topotactic reduction with CaH2 co-anneals under high oxygen pressure (100-102 MPa). This strategy enables the effective growth of IL nickelates incorporating heavier rare-earth elements that are otherwise difficult to incorporate.

Terminology used across episodes

This episode discusses

The paper

A chemical avenue to manipulate field-reentrant superconducting rivalries in infinite layer nickelates · Read on arXiv

Haowen Han, Yusong Zhao, Yi Bian, Tong Ma, Wenlong Yang, Shaohua Yang, Binghui Ge, Hongliang Dong,5,  Chuanying Xi6,  Ze Wang6,  Nuofu Chen7, ΔShang8, Toni Shiroka9, Zaher Salman9, Jia-Cai Nie2,10*, Ho-Kwang Mao4,5, and Jikun Chen1*, School of Materials Science and Engineering, University of Science and Technology Beijing, School of Physics and Astronomy, Beijing Normal University, Institute of Physical Science and Information Technology, Anhui University, Center for High Pressure Science and Technology Advanced Research, Shanghai Key Laboratory of Material Frontiers Research in Extreme Environments (MFree), Anhui Key Laboratory of Low-Energy Quantum Materials and Devices, High Magnetic Field Laboratory, Chinese Academy of Sciences, School of Renewable Energy, North China Electric Power University, Key Laboratory of Polar Materials and Devices (MOE), School of Physics and Electronic Science, East China Normal University, PSI Center for Neutron and Muon Sciences, Key Laboratory of Multiscale Spin Physics, Ministry of Education

University of Science and Technology Beijing · Beijing Normal University · Anhui University · Center for High Pressure Science and Technology Advanced Research · Shanghai Key Laboratory of Material Frontiers Research in Extreme Environments (MFree) · Anhui Key Laboratory of Low-Energy Quantum Materials and Devices, High Magnetic Field Laboratory, Chinese Academy of Sciences · School of Renewable Energy, North China Electric Power University · Key Laboratory of Polar Materials and Devices (MOE), School of Physics and Electronic Science, East China Normal University · PSI Center for Neutron and Muon Sciences · Key Laboratory of Multiscale Spin Physics, Ministry of Education

Transcript

Introduction to the show: ident: Quantum Radio. Generated commentary on the latest quantum physics and condensed matter papers.

Kai: We're looking at the paper: "A chemical avenue to manipulate field-reentrant superconducting rivalries in infinite layer nickelates".

Mira: The gist: A chemical avenue to manipulate field-reentrant superconducting rivalries in infinite layer nickelates elucidates how RE-4f orbital and spin interplays modulate quantum phase criticality and pairing strength,

Kai: First, who's behind it and why it matters.

Paper summary: Kai: To build on what we just heard, this paper, "A chemical avenue to manipulate field-reentrant superconducting rivalries in infinite layer nickelates," is essentially about finding a way to grow these materials effectively. The authors suggest that they can open up chemical avenues for effective growth of (RE1-yRE'y)one-xEuxNiO2, which includes Pr, Nd, Sm, Gd, Dy as the rare earths <ref:2511.22026#pg1>.

Mira: They are using a high-pO2 assisted chemical strategy to grow these infinite layer nickelates. The goal is to reduce the positive energy change of perovskite nickelates contracting when you introduce lanthanide contractions by using this high-pO2 approach for thin film growth of IL nickelate.

Lev: The way they do it involves dissolving the chemical precursors like RE(NO3)three and Ni(CH3COO)two in ethylene glycol monomethyl ether, EGME, and then spin coating them on a NdGaO3 substrate <ref:2511.22026#pg1>.

Kai: Then they transform the perovskite nickelates into infinite layer structure through soft chemical topotactic reduction based on CaH2 co-anneals instead of just using conventional alkaline earth elements like Sr or Ca.

Mira: And interestingly, instead of using those elements for hole doping, they realize it by partially substituting their RE constituents with Europium, which changes its valence state from plus three in the perovskites to plus two upon topotactic reduction.

Lev: From a thermodynamic view, the metastable perovskite nickelates precursors containing later series RE composition are preferentially stabilized at a high-pO2 within one hundred to one hundred and two mega pascals.

Kai: So, this chemical strategy allows them to put later series rare earths even further behind Europium in the infinite layer nickelates, and the RE constituent is just flexible enough to modulate by changing the chemical solutions for spin coating.

Mira: That flexibility is key because it lets them study how RE 4f-related quantum competition between high-Tc and reentrant superconductivity plays out <ref:2511.22026#pg1>.

Lev: It’s a very specific set of conditions they are creating to reach these systems, which is important for us because it sets the actual physical limits for what we can measure on real hardware.

Conclusion: Kai: So, looking at "A chemical avenue to manipulate field-reentrant superconducting rivalries in infinite layer nickelates," the authors are showing that this specific chemical approach is a new way to access these complex behaviors in nickelates.

Mira: They are emphasizing how this avenue allows them to enrich the superconducting phase diagram by seeing field-reentrant states emerge at both quantum boundaries, where high-Tc and reentrant superconductivity compete for dominance.

Lev: The implication for us is that it shows the quantum criticality between those two types of superconductivity isn't just about how much Europium you put in, but also about how the RE magnetism modulates that exchange field.

Kai: That’s right, and combining their magneto-transport measurements with low-energy muon spin spectroscopy reveals that there is this simultaneous occurrence of strengthened Cooper pairing and promoted magnetic fluctuation through the optimal Eu2+-4f7 interactions <ref:2511.22026#pg2>.

Mira: This interaction is what leads to the elevated Tc up to about forty Kelvin compared to those Sr or Ca doped systems, even when the layer spacing is similar <ref:2511.22026#pg2>.

Lev: So, this suggests a new freedom in understanding how RE 4f orbital and spin interplay can complicate the superconducting phase diagram of infinite layer nickelates in terms of quantum phase criticality modulation and pairing strengthening <ref:2511.22026#pg1>.

Kai: And it has practical implications because they showed that non-vacuum growth of IL-nickelate with high effectiveness is something that could be leveraged for technologies similar to cuprates.

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