Generalized mean-field theory for metals and semiconductors with magnetic impurities

Random systems of magnetic moments positioned in cites of a crystal lattice and interacting via RKKY- or Bloembergen-Rowland-type interaction are considered in the framework of generalized mean-field theory (GMFT) based on calculating and analyzing distribution functionsF(H) of random local magnetic fields H. For concentrated systems (where the random local field is produced by a number of interacting magnetic moments), the function F(H) turns out to be Gaussian one and all information about the system is contained in two parameters of that distribution only-it's width and maximum position. For rarefied systems (where the average distance between interacting moments is comparable with or larger than the interaction length), distribution functions are essentially non-Gaussian. GMFT has been applied for calculating the magnetic state of metals and semiconductors diluted with magnetic impurities.