Cluster-glass freezing and antiferromagnetic phase transitions in corundum structure Mg3−xCoxTeO6

Abstract

We investigate polycrystalline powder samples of the Co-substituted Mg3−xCoxTeO6 (x = 0.0–2.4) by X-ray diffraction, magnetic susceptibilities, and specific heat. The non-magnetic parent compound Mg3TeO6 crystallizes in the trigonal R3¯ space group. All Co-substituted samples have a similar crystal structure as the parent compound. The Rietveld refinements of synchrotron X-ray diffraction data reveal distorted (Mg/Co)O6 and TeO6 octahedra. Remarkably, we find the evolution of a magnetic phase from a non-magnetic ground state to an antiferromagnetic order through a cluster glass. The antiferromagnetically ordered state emerges above the percolation threshold (x ≥ 1.0), while the cluster glass state is stabilized for x = 0.8. © 2023 Elsevier B.V.