Influence of nickel substitution on the crystal structure of CuCr 2Se 4

Abstract

Substitution of divalent nickel ions in the spinel structure of CuCr 2Se 4 results in fundamental changes of the crystal structure from cubic to monoclinic symmetry. The investigations were conducted in the two systems: Cu 1− x Ni x Cr 2Se 4 (for x=0.1–0.9) and CuCr 2− x Ni x Se 4 (for x=0.1–2.0). When copper was substituted with nickel, a change in crystal structure was observed as the amount of doped nickel (from spinel-type structure to Cr 3S 4-type structure) was increased. When chromium was substituted with nickel, no change in crystal structure was observed. For x=0.1–0.9 just the spinel phase exists. For x≥1.0 the single-phase CuCr 2− x Ni x Se 4 compounds do not exist.