Correlation between electrical and magnetic properties of phase-separated manganites studied with a general effective medium model

We have performed electrical resistivity and DC magnetization measurements as a function of temperature, on polycrystalline samples of phase-separated La5/8-y Pr y Ca3/8MnO3 (y=0.3). We have used the general effective medium theory to obtain theoretical resistivity vs. temperature curves corresponding to different fixed ferromagnetic (FM) volume fraction values, assuming that the sample is a mixture of typical metallic-like and insulating manganites. By comparing this data with our experimental resistivity curves we have obtained the relative FM volume fraction of our sample as a function of temperature. This result matches with the corresponding magnetization data in excellent agreement, showing that a mixed-phase scenario is the key element to explain both the magnetic and transport properties in the present compound