Transport and magnetic properties in ferromagnetic manganese-oxide thin films

摘要

The transport and magnetic properties in ferromagnetic manganese-oxide thinfilms are studied based on the model of the coupling between the mobiled-electrons and the core spins in Mn ions. The spontaneous magnetization andthe resistivity are obtained for various magnetic fields and temperature. Theresistivity in absence of magnetic field and the magnetoresistance exhibitmaxima near the Curie temperature, the applied magnetic field moves theposition of the resistivity peak to high temperature and suppresses the peakvalue, which agree with the experimental results. The Hall resistivity ispredicted to exhibit maximum near the Curie point. The pressure effect of themagnetoresistance can also be explained qualitatively in this mechanism. Thecolossal magnetoresistance in ferromagnetic manganese-oxide thin films isattributed to the spin-correlation fluctuation scattering and the lowdimensional effect.