Is La<sub>3</sub>Ni<sub>2</sub>O<sub>6.5</sub> a Bulk Superconducting Nickelate?
Ran Gao, Lun Jin, Shuyuan Huyan, Danrui Ni, Haozhe Wang, Xianghan Xu, Sergey L. Bud’ko, P. C. Canfield, Weiwei Xie, R. J. Cava
Abstract
High Resolution Image Download MS PowerPoint Slide Superconducting states onsetting at moderately high temperatures have been observed in epitaxially stabilized RE NiO 2 -based thin films. However, recently, it has also been reported that superconductivity at high temperatures is observed in bulk La 3 Ni 2 O 7-δ at high pressure, opening further possibilities for study. Here we report the reduction profile of La 3 Ni 2 O 7 in a stream of 5% H 2 /Ar gas and the isolation of the metastable intermediate phase La 3 Ni 2 O 6.45, which is based on Ni 2+ . Although this reduced phase does not superconduct at ambient or high pressures, it offers insights into the Ni-327 system and encourages future study of nickelates as a function of oxygen content.