Abstract
Ferromagnetic semiconductor contains both local moment and itinerant carrier spins. Here we study the magnetization curveof these two subsystems as a function of temperature with two methods: Weiss mean field approach and Green's function approach. We find there are some similar points between these two approach in our results, and qualitatively agree with experimental deta. Also we caculate the effective interaction between two impurity spins (ie. local moment) through the linear response theory. Since there are intrinsic magnetic field in the system below critical temperature, which will cause the effective interaction have spiral-like response, instead of RKKY-like interaction.