Magnetoresistance in bicrystal grain-boundary junctions analyzed within the Stoner–Wohlfarth model

Experimental data of bicrystal grain boundary magnetoresistance hysteresis shows that the resistance at remanence after saturation depends on whether the magnetic field was applied parallel or perpendicular to the grain boundary. In the latter case the behaviour can be described by the Stoner-Wohlfarth magnetization reversal model for coherent rotation of the magnetization, which leads to an alignment along the easy magnetization directions of the bicrystal in zero field. In the parallel configuration the magnetization directions of the two grains remain parallel in zero field. We have used this information to deduce an effective spin-polarization of P ~ 40 % of the grain boundary in a bicrystal of La0.7Sr0.3MnO3.