ニッケル酸化物高温超伝導体のマイスナー反磁性測定

抄録

This paper investigates the superconducting properties of the bilayer nickelate La₂PrNi₂O₇ and its superconducting properties under high pressure. The polycrystalline samples were synthesized by the sol-gel method and measured using multi-anvil high-pressure techniques. In the pressure range of 18–20 GPa, superconductivity is strongly enhanced, with T_c^onset reaching 82.5 K and T_c^zero attaining 60 K. AC magnetic susceptibility measurements confirmed bulk superconductivity, showing a remarkably high superconducting shielding volume fraction of ~97 %. The introduction of Pr³⁺ ions effectively suppresses the intergrowth with other competing Ruddlesden-Popper phases and stabilizes the bilayer Ni–O octahedral layers, thereby enabling robust superconducting behavior. These findings provide compelling experimental evidence for pressure-induced high-T_c bulk superconductivity in bilayer nickelates and contribute to understanding the structure-property relationship in this emerging class of superconductors.