Preparation\nand Characterization of a High-Entropy\nMagnet, (Mg, Mn, Co, Ni, Cu)<sub>3</sub>TeO<sub>6</sub>

We report on the synthesis of Mg<sub>0.6</sub>Mn<sub>0.7</sub>Co<sub>0.7</sub>Ni<sub>0.6</sub>Cu<sub>0.4</sub>TeO<sub>6</sub>, which is\nisostructural with multiferroic Mn<sub>3</sub>TeO<sub>6</sub> (space\ngroup R3̅). Study of its magnetic properties indicates\nestablishment of the long-range antiferromagnetic order at 16.3 K,\nslightly lower than that of pure Mn<sub>3</sub>TeO<sub>6</sub>. The\ntiny hysteresis of magnetization loop along with specific heat data\nimplies the presence of ferromagnetic magnons at low temperatures.\nDielectric measurements reveal sequence of well-defined steps in the\nreal part of permittivity and peaks in the imaginary parts of permittivity\nat 30, 92, and 212 K attributable to the highly diffused structural\nchanges, which are characteristic to relaxor ferroelectrics. It is\nshown that usual interpretation of this structure type as corundum-related\nis not accurate: the hexagonal oxygen packing is not close and is\nnot double-layered. Therefore, Mn<sub>3</sub>TeO<sub>6</sub> represents\na very special structure type.