Field re-entrant superconductivity in Eu-doped infinite-layer nickelates

Area of Science:

• Condensed Matter Physics
• Materials Science
• Quantum Materials

Background:

• Intertwined superconducting and magnetic orders can lead to exotic quantum phases.
• Magnetism-enhanced superconductivity is rare in high-transition-temperature superconductors.
• Infinite-layer nickelates are a new class of unconventional superconductors, but the role of rare-earth magnetism is underexplored.

Purpose of the Study:

• To investigate the impact of rare-earth magnetism on superconductivity in infinite-layer nickelates.
• To explore the possibility of magnetism-enhanced superconductivity in this material class.
• To characterize the observed superconducting phases and their relationship with magnetic order.

Main Methods:

• Synthesis and characterization of Eu-doped infinite-layer nickelate Sm_0.95-xCa_0.05Eu_xNiO₂.
• Electrical transport measurements (zero-resistance, nonlinear Hall effect, hysteretic magnetoresistance).
• Magnetic susceptibility measurements (diamagnetic screening).

Main Results:

• Observation of a magnetic-field-induced re-entrant superconducting phase in the Eu-rich, over-doped regime.
• Confirmation of superconductivity via zero-resistance and diamagnetic screening.
• Evidence of unconventional behavior, including nonlinear Hall transport and hysteretic magnetoresistance, deviating from simple compensation models.

Conclusions:

• Infinite-layer nickelates serve as a promising platform for studying magnetically driven superconductivity.
• The observed re-entrant superconductivity highlights the complex interplay between magnetism and superconductivity.
• Further research into these strongly correlated oxides can uncover novel quantum phenomena.