Enhanced Magnetic Interaction by Face-Shared Hydride Anions in 6H-BaCrO2H

Kentaro Higashi; Masayuki Ochi; Yusuke Nambu; Takafumi Yamamoto; Taito Murakami; Naoya Yamashina; Cédric Tassel; Yuki Matsumoto; Hiroshi Takatsu; Craig M Brown; Hiroshi Kageyama

doi:10.1021/acs.inorgchem.1c00992

Enhanced Magnetic Interaction by Face-Shared Hydride Anions in 6H-BaCrO₂H

Inorg Chem. 2021 Aug 16;60(16):11957-11963. doi: 10.1021/acs.inorgchem.1c00992. Epub 2021 Jul 26.

Authors

Affiliations

¹ Graduate School of Engineering, Kyoto University, Kyoto 615-8510, Japan.
² Department of Physics, Osaka University, Machikaneyama-cho, Toyonaka, Osaka 560-0043, Japan.
³ Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan.
⁴ FOREST, Japan Science and Technology Agency, Kawaguchi, Saitama 332-0012, Japan.
⁵ Japan Organization for Advanced Studies, Tohoku University, Sendai 980-8577, Japan.
⁶ Center for Neutron Research, National Institute of Standards and Technology (NIST), Gaithersburg, Maryland 20899, United States.

PMID: 34309363
DOI: 10.1021/acs.inorgchem.1c00992

Abstract

Studies on magnetic oxyhydrides have been almost limited to perovskite-based lattices with corner-sharing octahedra with a M-H-M (M: transition metal) angle of θ ∼ 180°. Using a high-pressure method, we prepared BaCrO₂H with a 6H-type hexagonal perovskite structure with corner- and face-sharing octahedra, offering a unique opportunity to investigate magnetic interactions based on a θ ∼ 90° case. Neutron diffraction for BaCrO₂H revealed an antiferromagnetic (AFM) order at T_N ∼ 375 K, which is higher than ∼240 K in BaCrO_3-xF_x. The relatively high T_N of BaCrO₂H can be explained by the preferred occupancy of H^- at the face-sharing site that provides AFM superexchange in addition to AFM direct exchange interactions. First-principles calculations on BaCrO₂H in comparison with BaCrO₂F and BaMnO₃ further reveal that the direct Cr-Cr interaction is significantly enhanced by shortening the Cr-Cr distance due to the covalent nature of H^-. This study provides a useful strategy for the extensive control of magnetic interactions by exploiting the difference in the covalency of multiple anions.