Magnetoimpurity theory of manganites and other colossal magnetoresistance materials

A critical review is given of the physics of colossal magnetoresistance (CM R) materials (manganites and other degenerate ferromagnetic semiconductors) . The basic idea is that their specific properties (the resistivity peak cl ose to T-C, CMR and so on) are not related to the electron-lattice interact ion but are caused by static fluctuations of the magnetisation induced by i onised donors or accepters. Their screening by charge carriers causes fluct uations of their density and, hence, fluctuations of the intensity of indir ect exchange via them. The fluctuations of the magnetisation induced by the latter are maximally close to T-C, which explains the specific features of these materials.