The theory analysis of the field dependence of the magnetoresistance of La0.7Ca0.3MnO3 film

Abstract The field dependence of the magnetoresistance of the magnetic perovskite La 0.7 Ca 0.3 MnO 3 film has been analyzed by using a negative-magnetoresistivity scaling deduced from Mott’s model. The fitting is made and the Curie temperature is determined more precisely. Through analyzing the variation of the magnetoresistance (MR) with respect to some physics parameters, the relations between the value of MR ratio and the size of the magnetically aligned cluster are revealed. Moreover, the behaviors of the fit parameters J ( T ) and the magnetically aligned clusters are investigated. We find that with the paramagnetic-ferromagnetic transition a sudden change in the value of J ( T ) and in the size of the magnetically aligned clusters occurs.