Magneto-optical imaging of elastic strain-controlled magnetization reorientation

We study strain-controlled magnetization-reorientation processes in nickel thin film/piezoelectric actuator hybrid structures. To obtain a consistent picture of the connection between magnetic microstructure and magnetoresistance, we correlate simultaneously measured spatially resolved magneto-optical Kerr effect imaging and integral magnetotransport measurements at room temperature. Our results show that the magnetization predominantly reorients by coherent rotation as a function of the voltage applied to the hybrid, except for a narrow region around the coercive field for which the magnetization reorientation evolves via domain effects. This demonstrates that both magnetic-field and strain-driven magnetization reversal can be modeled in terms of a macrospin model.