Correlations of the magnetic and electrical properties with the ionic radii of cations and anions for the series of ternary and quaternary spinel-type chromium compounds

Abstract

For the compounds ACr 2X 4 (where: A=Cd, Zn, Hg, Ga, Cu; X=O, S, Se, Te), ACr 2 x B 2−2 x X 4 (where: A=Cd, Zn; B=Ga, In; X=S, O), ZnCr 2− x In x Se 4 and Cr 2V 4− x Mo x O 13+0.5 x correlations were observed of the magnetic and electrical properties with the ionic radii of their cations and anions, whereas for the solid solutions of the boundary compounds ACr 2X 4 (where: A=Cd, Zn; X=S, Se, Te) and CuCr 2X 4 (were X=S, Se, Te) not only such correlations but also the metallic conductivity and a semiconductor–metal phase transition were observed. In particular for Zn 1− x Cu x Cr 2Se 4 this phase transition is accompanied by the magnetic AF-F phase transition, while for Cd 1− x Cu x Cr 2Se 4 one deals with the accompanying Fi-F phase transition. In the latter spinel series there exists the ferrimagnetic ordering at low copper concentrations, whereas at high copper concentrations one deals with the ferromagnetic ordering.