Chemical aspect of the structural disorder in CuCrS2 and CuCr1–x V x S2 solid solutions

A gradient chemical structure of micron-sized crystals of CuCrS2 and CuCr1–x V x S2 powders is established by the differential dissolution technique. It is shown that their surface region coherently conjugated with planar faces of CuCrS2 crystals is enriched with copper whereas the bulk is depleted of copper and the copper sublattice is disordered. A possible mechanism of the formation of surface regions due to a high bulk mobility of copper atoms in the defect copper sublattice is proposed. It is shown that for solid solutions the disordering process involves copper and vanadium atoms and vacancy complexes. The phenomena found are discussed together with the structural and magnetic data.