THE TEMPERATURE-DEPENDENCE OF THE SURFACE ANISOTROPY ENERGY OF AMORPHOUS THIN-FILMS

Surface excitation in r. f. -sputtered thin amorphous (Gd//1// minus xCo//x)//1// minus //yMo//y films was studied. A microwave spectrometer operating in the X band was used for magnetic resonance investigations: the external magnetic field was rotated from perpendicular to parallel resonance orientation. The critical angle and angular dependence of the position of the surface mode and the uniform mode were determined. The surface inhomogeneity model was applied with symmetrical boundary conditions. The temperature dependences of the uniaxial surface anisotropy constant and the biaxial surface anisotropy constant were found from the results of these experiments. The uniaxial anisotropy energy varies with temperature and changes sign from easy axis to easy plane at y equals 0. 02, whereas the biaxial surface anisotropy does not change character.