2025/10/14 by Qiu, Zhengyang, Chen, Junfeng, Semenok, Dmitrii V. +12 · 3 citations
#FOS: Physical sciences #Superconductivity (cond-mat.supr-con)
paper · doi:10.48550/arxiv.2510.12359
Systematically controlling the superconducting transition temperature (Tc) in the bilayer Ruddlesden-Popper nickelate La3Ni2O7 remains a significant challenge. Here, we address this by synthesizing high-quality polycrystalline La3-xNdxNi2O7 (0 ≤ x ≤ 2.4) with record-level rare-earth substitution. Nd doping compresses the lattice, particularly along the c axis, enhances the spin density wave transition temperature, and elevates the pressure required for the orthorhombic-to-tetragonal structural transition. Superconductivity is observed across all doping levels under high pressures, with the onset Tc rising to ∼93~K for x = 2.1 and 2.4 from the electronic transport measurement. Using the radio-frequency transmission technique, newly applied to nickelate superconductors, we detect signatures of superconductivity at 98 ± 2~K in the x=2.4 compound, pushing the Tc frontier further. We identify a universal linear relationship where Tc decreases with the c-axis lattice parameter at a rate of approximately -28~K/Å, demonstrating that enhanced interlayer magnetic exchange coupling is the dominant mechanism for superconducting pairing. Our work establishes the critical role of magnetism and provides a unified structural descriptor for elevating Tc in bilayer nickelates.