Transport and magnetic properties in ferromagnetic manganese-oxide thin films

TL;DR

This paper models the transport and magnetic behaviors of ferromagnetic manganese-oxide thin films, explaining phenomena like magnetoresistance and Hall resistivity peaks near the Curie temperature through spin interactions and low-dimensional effects.

Contribution

It introduces a theoretical model linking d-electron and core spin coupling to explain magnetic and transport properties in manganese-oxide thin films.

Findings

Resistivity peaks near Curie temperature shift with magnetic field.

Magnetoresistance and Hall resistivity exhibit maxima near Curie point.

Colossal magnetoresistance is explained by spin fluctuations and low-dimensional effects.

Abstract

The transport and magnetic properties in ferromagnetic manganese-oxide thin films are studied based on the model of the coupling between the mobile d-electrons and the core spins in Mn ions. The spontaneous magnetization and the resistivity are obtained for various magnetic fields and temperature. The resistivity in absence of magnetic field and the magnetoresistance exhibit maxima near the Curie temperature, the applied magnetic field moves the position of the resistivity peak to high temperature and suppresses the peak value, which agree with the experimental results. The Hall resistivity is predicted to exhibit maximum near the Curie point. The pressure effect of the magnetoresistance can also be explained qualitatively in this mechanism. The colossal magnetoresistance in ferromagnetic manganese-oxide thin films is attributed to the spin-correlation fluctuation scattering and the low dimensional effect.