REENTRANT TRANSITION AND SPIN-GLASS STATE IN CDCR2XIN2-2XSE4 THIN-FILMS

Magnetic properties of polycrystalline thin films of chromium chalcogenide spinels, i.e., CdCr2Se4 lightly doped with indium and CdCr2(x)In(2-2x)Se4, are studied. The ferromagnetic- and spin-wave-resonance techniques have been used to investigate the temperature dependences of the spin-wave stiffness constant D, the saturation magnetization M(s), and the resonance linewidth GAMMA. The resonance spectra have been recorded in the temperature range extending from 4.2 to 300 K. The influence of indium concentration on M(s)(T), D(T), and r(T) is studied. It is shown that lightly doped samples ([In]/[Cd] < 1%) exhibit ferromagnetic ordering, with M(s)(T) and D(T) being linear functions of T3/2 and T5/2, respectively. A higher concentration of indium produces the reentrant transition and spin-glass state of magnetic ordering in CdCr2(x)In(2-2x)Se4. A numerical analysis of the saturation magnetization and linewidth temperature dependence has been performed in order to determine the type of magnetic ordering.