We studied current induced magnetization reversal in elliptical spin valves with CoFeB free layers. The data obtained from high-speed pulsed switching experiments, where the pulse widths were varied from 0.1 to 5 ns, showed differences in the intrinsic switching current density for devices of different sizes and aspect ratios. The values of the intrinsic switching currents as well as their dependence on size and shape can not be adequately explained by a single domain model. Experimental values for the intrinsic switching current densities were 50% to 100% higher than predicted by a single domain model. Micromagnetic simulations reveal a complex behavior of magnetization switching in which end mode oscillations are important and indicate that the switching current density is dependent on the device dimensions. Experimental values for the intrinsic switching current density agree with those predicted by micromagnetic simulations.
Citation: Applied Physics Letters
Pub Type: Journals
Current induced magnetization reversal, spin valve, MRAM, micromagnetic modeling