SEMICONDUCTOR SPIN-GLASSES CU2/3GE1/3CR2S4 AND CU0.5IN0.5CR2SE4 - CRITICAL-BEHAVIOR AND GIANT NEGATIVE MAGNETORESISTANCEстатья
Информация о цитировании статьи получена из
Scopus,
Web of Science
Статья опубликована в журнале из списка Web of Science и/или Scopus
Дата последнего поиска статьи во внешних источниках: 18 июля 2013 г.
Аннотация:The compounds Cu2/3Ge1/3Cr2S4 and Cu0.5In0.5Cr2Se4 have been shown to possess magnetic properties characteristic for spin glasses (SG). The critical behaviour of these compounds have been studied by means of the nonlinear susceptibility chi(n1) in the region of freezing temperature T(f) that is defined as the temperature of maximum on the chi(n1)(T) curve. The critical exponents gamma, delta and beta have been determined. The temperature T(f)' of the maximum on the curves for the dependences of the initial susceptibility on T measured in an ac magnetic field has been found to depend on the frequency of measurements, according to the Vogel-Fulcher law, the constant T0 being equal to T(f). In these semiconductor compounds the giant negative isotropic magnetoresistance DELTArho/rho has been observed, that reaches 80% at H = 30 kOe. A maximum in T(f) has been observed on the dependence DELTArho/rho(T), which is similar to that DELTArho/rho(T) in the region of magnetic ordering temperature in magnetic semiconductors.