posted on 2023-09-20, 14:05authored byHaozhe 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.