Magnetization Processes Revealed by In-Plane DC Magnetoresistance Measurements on Manganite Bicrystal Thin Film Devices

Magnetic bicrystal grain boundary junctions can be used as model systems for magnetic tunnel junctions. We demonstrate how the magnetization reversal process indirectly can be found from dc magnetoresistance measurements in manganite bicrystal junctions. The results are discussed in terms of a micromagnetic energy balance. We find that the magnetization reversal strongly depends on the direction of the magnetic field. With the field applied parallel to the grain boundary the magnetization hysteresis is determined by a Barkhausen-like reversal process. In the perpendicular configuration the hysteresis can be modelled as a Stoner-Wohlfart rotation.