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

摘要

For the compounds ACr_2X_4 (where: A=Cd, Zn, Hg, Ga, Cu; X=O, S, Se, Te). ACr_(2x)B_(2-2x)X_4 (where: A=Cd, Zn; B=Ga, In; X=S, O), ZnCr_(2-x) In_xSe_4 and Cr_2V_(4-x)Mo_xO_(13+0.5x) 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_xCr_2Se_4 this phase transition is accompanied by the magnetic AF-F phase transition, while for Cd_(1-x)Cu_xCr_2Se_4 one deals with the accompanying Fi-F phase transition. In the latter spinet series there exists the ferrimagnetic ordering at low copper concentrations, whereas at high copper concentrations one deals with the ferromagnetic ordering.