American Chemical Society
ja3c08726_si_003.mp4 (549.79 kB)

Impersonating a Superconductor: High-Pressure BaCoO3, an Insulating Ferromagnet

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posted on 2023-09-20, 14:05 authored by Haozhe Wang, Xianghan Xu, Danrui Ni, David Walker, Jie Li, Robert J. Cava, Weiwei Xie
We report the high-pressure synthesis (6 GPa, 1200 °C) and ambient-pressure characterization of hexagonal HP-BaCoO3. The material (with a 2H crystal structure) has a short intrachain Co–Co distance of about 2.07 Å. Our magnetization investigation revealed robust diamagnetic behavior below approximately 130 K when the material was exposed to weak applied magnetic fields (10 Oe) and a distinct “half-levitation” phenomenon below that temperature, as is often observed for superconductors. Its field-dependent magnetization profile, however, unveils the characteristics of ferromagnetism, marked by a substantial magnetic retentivity of 0.22(1) μB/Co at a temperature of 2 K. Electrical resistivity measurements indicate that HP-BaCoO3 is a ferromagnetic insulator, not a superconductor.