MAGNETIC SUPEREXCHANGE INTERACTIONS AND METAMAGNETIC PHASE-TRANSITIONS IN THE SINGLE-CRYSTALS OF THE SPINELS ZNCR2-XINXSE4 ESS-THAN-OR-EQUAL-TO-X-LESS-THAN-OR-EQUAL-TO-0.14)

The experimental data for the magnetization and the magnetic susceptib ility, as well as their dependence on temperature, on the induction of the external magnetic field and on the concentration x have been anal yzed. The metamagnetic phase transitions induced by the external magne tic field have been observed as plateau areas and jump-like increments on the magnetization curves at 4.2 K. High values of the effective ma gnetic moment mu(eff) and of the Curie constant C-M point to the exist ence of Cr2+ ions as well as Cr3+ ions. The exchange constants, transf er integrals and the spiral angles for the solid solutions under study have been evaluated.