Temperature dependence of surface magnetic anisotropy energy constant in magnetic semiconductor thin films

Abstract

We report on temperature dependence of surface magnetic anisotropy energy constant in magnetic semiconductor thin films of CdCr 2−2 x In 2 x Se 4 at spin glass state. Coexistence of the infinite ferromagnetic network (IFN) and finite spin clusters (FSC) in the spin glass state (SG) is a known phenomena. The spin wave resonance experiment (microwave spectrometer at X-band) with excited surface modes was applied to describe the energy state of surface spins. We determined the surface magnetic anisotropy energy constant versus temperature using the surface inhomogeneities model of magnetic thin films. It was found that two components contribute to the surface energy. One originates from the exchange interaction term due to the lack of translation symmetry for surface spin as well as from the surface stray field of the surface roughness. The second one comes from the demagnetizing field of the close-to-surface layer with grad M. Both terms of surface magnetic anisotropy energy, decrease when the temperature is increased from 5 to 125 K, but the dominant contribution is from the first compound.