Carrier-induced ferromagnetism in concentrated and diluted local-moment systems

摘要: For modeling the magnetic properties of concentrated and diluted semiconductors, we use Kondo-lattice model. The phase diagram is derived by inspecting static susceptibility itinerant band electrons, which are exchange coupled to localized moments. It turns out that rather low occupations favor a ferromagnetic ordering local moment systems due an indirect coupling mediated spin polarization charge carriers. disorder in treated adding CPA-type concept theory. almost all concentrations $x$, ferromagnetism possible, however, only for carrier $n$ distinctly smaller than $x$. compensation real semiconductors (in ${\mathrm{Ga}}_{1\ensuremath{-}x}{\mathrm{Mn}}_{x}\mathrm{As}$ by, e.g., antisites) seems be necessary condition getting induced ferromagnetism.