Double-peaked character of the temperature dependence of resistance of perovskite manganites for a broadened ferromagnetic transition

The behavior of a system consisting of a mixture of paramagnetic semiconduc ting and ferromagnetic metallic phases is examined in the framework of the percolation model. As the temperature decreases below the Curie point, the paramagnetic phase fraction is assumed to decreases according to an exponen tial law. The evolution of the temperature variation of the resulting resis tance is considered as a function of the magnetic transition broadening. An explanation is offered for the low-temperature resistance anomaly observed experimentally in a number of perovskite manganites. (C) 1999 American Ins titute of Physics. [S1063-777X(99)00612-X].