Low-Field Magnetoresistance In Perovskite Manganites: Magnetic Field, Temperature, And Current Dependence

The low-field response from single bicrystal grain boundary junction of La0.7Sr0.3MnO3 has been investigated. We provide experimental data for the temperature, magnetic field, and bias current dependence of its low-field magnetoresistance. We are then able to separate the contribution from anisotropic magnetoresistance, and the magnetization processes in the vicinity of the grain boundary. Our data indicate that with the magnetic field applied parallel to the grain boundary the magnetization process is dominated by domain-wall motion, whereas with the field in the perpendicular direction the magnetoresistance is determined by coherent rotation of magnetization directions.