Localized Spin Dimers and Structural Distortions in the Hexagonal Perovskite Ba 3 CaMo 2 O 9

• Published in: Inorganic chemistry Vol. 61; no. 30; pp. 11622 - 11628
• Main Authors: Simpson, Struan, Milton, Michael, Fop, Sacha, Stenning, Gavin B G, Hopper, Harriet Alexandra, Ritter, Clemens, Mclaughlin, Abbie C
• Format: Journal Article
• Language: English
• Published: United States 01.08.2022
• ISSN: 0020-1669; 1520-510X
• DOI: 10.1021/acs.inorgchem.2c01102

Extended solid-state materials based on the hexagonal perovskite framework are typified by close competition between localized magnetic interactions and quasi-molecular electronic states. Here, we report the structural and magnetic properties of the new six-layer hexagonal perovskite Ba CaMo O . Neutron diffraction experiments, combined with magnetic susceptibility measurements, show that the Mo O dimers retain localized character down to 5 K and adopt nonmagnetic spin-singlet ground states. This is in contrast to the recently reported Ba SrMo O analogue, in which the Mo O dimers spontaneously separate into a mixture of localized and quasi-molecular ground states. Structural distortions in both Ba CaMo O and Ba SrMo O have been studied with the aid of distortion mode analyses to elucidate the coupling between the crystal lattice and electronic interactions in 6H Mo hexagonal perovskites.