Structural Chemistry and Magnetic Properties of the Hexagonal Double Perovskite Ba2CoOsO6

Paula Kayser; Fabio Orlandi; Maxim Avdeev; Zhaoming Zhang; Justin A Kimpton; Brendan J Kennedy

doi:10.1021/acs.inorgchem.0c00761

Structural Chemistry and Magnetic Properties of the Hexagonal Double Perovskite Ba₂CoOsO₆

Inorg Chem. 2020 May 4;59(9):6613-6622. doi: 10.1021/acs.inorgchem.0c00761. Epub 2020 Apr 14.

Authors

Paula Kayser^{1

2}, Fabio Orlandi³, Maxim Avdeev^{1

4}, Zhaoming Zhang⁴, Justin A Kimpton⁵, Brendan J Kennedy¹

Affiliations

¹ School of Chemistry, The University of Sydney, Sydney, New South Wales 2006, Australia.
² Centre for Science at Extreme Conditions and School of Chemistry, The University of Edinburgh, Edinburgh EH9 3JZ, U.K.
³ ISIS Facility, STFC Rutherford Appleton Laboratory, Harwell Oxford, Didcot, Oxon OX11 0QX, U.K.
⁴ Australian Nuclear Science and Technology Organisation, Lucas Heights, New South Wales 2234, Australia.
⁵ Australian Synchrotron, Australian Nuclear Science and Technology Organisation, 800 Blackburn Road, Clayton, Victoria 3168, Australia.

PMID: 32286805
DOI: 10.1021/acs.inorgchem.0c00761

Abstract

The double perovskite Ba₂CoOsO₆, synthesized using solid-state methods at ambient pressure, is shown as a rare example of an oxide adopting the 6L-trigonal (S.G.: P3̅m1) perovskite structure. The structure, refined using a combination of X-ray and neutron diffraction data, showed the Co and Os were ordered over the two dimer sites with additional ordering over the corner-sharing sites. Bond valence calculations show the presence of the Co(II) and Os(VI) valence states, and the latter was confirmed using X-ray absorption spectroscopy. Bulk magnetic susceptibility measurements show Ba₂CoOsO₆ to undergo antiferromagnetic ordering near 100 K, and neutron diffraction showed an ordered moment on the Co3, Co4, and Os2 sites; whereas the Os1/Co1 remained disordered.