Tunneling magnetoresistance of Fe3O4 compacts prepared in magnetic field

The magnetite particles were prepared in magnetic field in order to improve the surface crystallinity and reduce the lattice defests of particles. The magnetotransport properties of as-prepared magnetite compact were investigated and compared with that prepared without magnetic field. Spin polarization tunneling and high order hopping conductance were the main conduct mechanisms. The resistance decreased almost exponentially with increasing temperature, and was noncollinearity dependent on the voltage. Magnetoresistance vs magnetic field curves were butterfly-like, which was characteristic of tunneling magnetoresistance. The results showed that the sample prepared in magnetic field had lower resistance and higher magnetoresistance, maybe due to the particles having better crystallinty in the surface and less lattice defect. Magnetoresistance of both samples decreased slowly with increasing temperature.