Source capture
Authors Haowen Han, Yusong Zhao, Yi Bian, Tong Ma, Wenlong Yang, Shaohua Yang, Binghui Ge, Hongliang Dong, Chuanying Xi, Ze Wang, Nuofu Chen, Tian Shang, Toni Shiroka, Zaher Salman, Jia-Cai Nie, Ho-Kwang Mao, Jikun Chen
arXiv / Publisher https://arxiv.org/abs/2511.22026
PDF https://arxiv.org/pdf/2511.22026
Relevance score 4.865
Primary category cond-mat.supr-con
Published 2026-06-30
Research paradigm Not available in this batch.
Sample form Not available in this batch.

Summary

This study developed a megapascal-level high-pressure oxygen-assisted chemical synthesis route that successfully enabled the effective growth of infinite-layer nickelates extending to heavier rare earth elements, with composition (RE1-yRE'y)1-xEuxNiO2 (RE/RE': Pr, Nd, Sm, Gd, Dy). Hole doping was realized through Eu2+/Eu3+ valence variation. At the superconducting dome boundaries of Nd1-xEuxNiO2 and Pr1-xEuxNiO2 systems, robust uniaxial anisotropic magnetic-field reentrant superconductivity was observed, arising from the competition between Eu2+ 4f7 magnetic moments and magnetic fluctuations, while the optimally doped regions exhibited conventional high-temperature superconductivity with a critical current density reaching ~266 kA/cm2 at 2 K, surpassing that of traditional Sr/Ca-doped systems. Further introduction of different RE′ magnetic ions allowed tuning of the exchange field strength and thereby modulation of quantum criticality, both enhancing the reentrant behavior and elevating T_c to 40.1 K. This work reveals the critical role of rare-earth 4f magnetic moments in modulating pairing strength and quantum criticality, establishing a synthetic foundation for utilizing the infinite-layer nickelate platform to investigate 4f-related unconventional superconductivity and quantum phase transitions.

Materials

Not available in this batch.

Methods

Not available in this batch.

Keywords

Not available in this batch.

Highlights

Not available in this batch.

Conclusions

Not available in this batch.

Main claims

  • A chemical avenue enables effective growth of (RE,RE')1-xEuxNiO2, revealing RE-4f-related quantum competition between high-Tc and reentrant superconductivity.
    • Evidence: 'Herein, we open up chemical avenues to enable effective growth of (RE1-yRE'y)1-xEuxNiO2 (RE/RE': Pr, Nd, Sm, Gd, Dy), giving rise to discoveries of RE-4f-related quantum competition between high-Tc and reentrant superconductivity.' (Abstract)
  • Robust magnetic-field-reentrant superconductivity with uniaxial anisotropy is observed at superconducting-dome boundaries, stemming from Eu2+-4f7 competition between magnetic-fluctuation promoted pairing and exchange-field interactions.
    • Evidence: 'Robust magnetic-field-reentrant superconductivity with uniaxial anisotropy is observed at superconducting-dome boundaries, stemming from Eu2+-4f7 associated competition between magnetic-fluctuation promoted pairing and exchange-field interactions.' (Abstract)
  • Quantum-criticality is further modulable via RE(RE')-magnetism, which either reinforces reentrancy or elevates Tc (40.1 K) with more robust critical-current-density (≈266 kA/cm2 at 2 K) beyond Sr-/Ca-doped counterparts.
    • Evidence: 'Their quantum-criticality is further modulable via RE(RE')-magnetism, which either reinforces reentrancy or elevates Tc (40.1 K) with more robust critical-current-density (≈266 kA/cm2 at 2 K) beyond Sr-/Ca-doped counterparts.' (Abstract)
  • Combining magneto-transport and LE-μSR unveils that strengthened Cooper pairing and promoted magnetic fluctuation via optimum Eu2+-4f7 interactions are responsible for elevated Tc and Jc beyond Sr/Ca systems.
    • Evidence: 'Further introduction of different RE′ magnetic ions allowed tuning of the exchange field strength and thereby modulation of quantum criticality, both enhancing the reentrant behavior and elevating T_c to 40.1 K.' (Summary),'combining magneto-transport and LE-μSR measurements unveils the concomitant occurrence of strengthened Cooper pairing and promoted magnetic fluctuation' (Conclusion paraphrase)

Workflow

  • Synthesis of infinite-layer nickelate thin films via high-pressure oxygen-assisted chemical route — Effective growth of (RE,RE')1-xEuxNiO2 infinite-layer nickelates with heavier rare-earths enabled by MPa-high-pO2 synthesis, overcoming thermodynamic limitations of vacuum epitaxy.
    • Materials: RE(NO3)3; Ni(CH3COO)2; ethylene glycol monomethyl ether (EGME); NdGaO3 (110) substrate; CaH2
    • Methods: spin coating; MPa-range high-pressure oxygen annealing; topotactic reduction with CaH2
    • Observations: Perovskite precursor films exhibit metal-insulator transitions (T_MIT increasing with Eu content); XRD confirms transformation to infinite-layer structure after reduction; Cross-section STEM shows ≈20 nm thick films with coherent interfaces; some reduced crystallinity
  • Transport measurements and superconducting phase diagram mapping — Robust magnetic-field-reentrant superconductivity with uniaxial anisotropy emerges at quantum boundaries of the superconducting dome, competing with high-Tc superconductivity, associated with Eu2+ 4f7 magnetic moments.
    • Materials: Nd1-xEuxNiO2 films; Pr1-xEuxNiO2 films
    • Methods: resistivity vs temperature under magnetic fields up to 35T; magnetic field-dependent resistivity mapping; critical current density measurements
    • Observations: Optimum-doped Nd0.55Eu0.45NiO2 shows conventional superconductivity with Tc,onset ≈37.6 K, monotonically suppressed by field; Underdoped (x=0.2-0.3) and overdoped (x=0.52-0.6) samples exhibit field-reentrant superconductivity, zero resistance re-emerging at high fields; Phase diagrams reveal reentrance exclusively at superconducting dome boundaries; Jc reaches 266 kA/cm2 at 2 K for optimum doping, robust under 9 T field
  • Modulation of reentrant behavior and Tc via rare-earth substitution — Quantum criticality between reentrant and high-Tc SC is tunable via RE' magnetism; Gd3+ (4f7) reinforces reentrancy via Jaccarino-Peter effect, while weak magnetic RE' mixing elevates Tc by disturbing spin ordering.
    • Materials: (Nd1-yRE'y)0.65Eu0.35NiO2 with RE' = Pr, Sm, Gd, Dy
    • Methods: same synthesis route; resistivity under magnetic field; angular-dependent magnetotransport
    • Observations: Gd-substituted samples (y=0.05,0.1,0.2) show enhanced field-reentrant superconductivity; Dy, Pr, Sm show conventional SC; Angular mapping reveals uniaxial anisotropy with reentrant region near c-axis; Introducing RE' with reduced magnetism (Pr, Sm, mixed) elevates Tc up to 40.1K
  • Muon spin spectroscopy and pairing mechanism investigation — Enhanced magnetic fluctuations and spin ordering at superconducting state in Eu-doped nickelates strengthen Cooper pairing, explaining elevated Tc and Jc beyond Sr/Ca-doped systems.
    • Materials: Nd0.6Eu0.4NiO2 film on LSAT (100) substrate
    • Methods: low-energy muon-spin spectroscopy (LE-μSR)
    • Observations: Abrupt increase in ZF relaxation rate λ_ZF below Tc, to ≈2.5 μs-1, much larger than Sr-doped counterparts (0.22-0.48 μs-1); Stretch exponent β decreases to ≈0.5-0.6, indicating spin-glass-like state below Tc