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arXiv · 1902.00833

Long range antiferromagnetic order in a rocksalt high entropy oxide

Junjie Zhang·Jiaqiang Yan·S. Calder·Qiang Zheng·Michael A. McGuire·D. L. Abernathy·Yang Ren·Saul H. Lapidus·Katharine Page·Hong Zheng·J. W. Freeland·John D. Budai·Raphael P. Hermann
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Abstract

We report for the first time the magnetic structure of the high entropy oxide $(Mg_{0.2}Co_{0.2}Ni_{0.2}Cu_{0.2}Zn_{0.2})O$ using neutron powder diffraction. This material exhibits a sluggish magnetic transition but possesses a long-range ordered antiferromagnetic ground state, as revealed by DC and AC magnetic susceptibility, elastic and inelastic neutron scattering measurements. The magnetic propagation wavevector is k=(1/2, 1/2, 1/2) based on the cubic structure Fm-3m, and the magnetic structure consists of ferromagnetic sheets in the (111) planes with spins antiparallel between two neighboring planes. Inelastic neutron scattering reveals strong magnetic excitations at 100 K that survive up to room temperature. This work demonstrates that entropy-stabilized oxides represent a unique platform to study long range magnetic order with extreme chemical disorder.

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Junjie Zhang, Jiaqiang Yan, S. Calder, Qiang Zheng, Michael A. McGuire, D. L. Abernathy, Yang Ren, Saul H. Lapidus, Katharine Page, Hong Zheng, J. W. Freeland, John D. Budai, Raphael P. Hermann. 2019-02-03. Long range antiferromagnetic order in a rocksalt high entropy oxide. https://doi.org/10.1021/acs.chemmater.9b00624

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