CONTRIBUTION OF THE CLOSE-TO-SURFACE GRAD(M) TO THE SURFACE MAGNETIC-ANISOTROPY ENERGY IN THIN-FILMS OF CDCR2-2XIN2XSE4

We applied spin-waves resonance technique in order to determine the te mperature dependence of the surface magnetic anisotropy energy constan t for thin films of CdCr2Se4 diluted by In. The partial derivative(n)M of the close-to-surface layer contributes to the surface magnetic ani sotropy energy originated from the surface demagnetizing held with an anisotropy energy constant K-s(d) = 4 pi M-2(partial derivative(n)M/M) d(2), where d is the thickness of the close-to-surface layer. We have found within the temperature range 4.2-80 K, that K-s(d) is linearly d ecreasing when the temperature is increasing.