Effects of radio-frequency current on critical fields for magnetization reversal in spin-torque devices

The application of radio-frequency (rf) currents in spin-torque devices allows control of magnetization reversal through frequency of the rf current. Using this effect, the impact of the rf currents on switching fields of nanostructured metallic spin valves has been investigated. The rf current injection was observed to change the critical field for free-layer magnetization reversal when the intrinsic spin-transfer-induced dynamics are frequency locked with the injected rf. Experimental results are presented by mapping the switching contour plot, and are compared with simulations in the context of macrospin models of spin transfer in metallic-spin-valve structures. Differences between this effect and the effect of rf currents on direct-current-induced magnetization reversal are highlighted by considering the role of a magnetization dispersion in the two sweep methods, which allows insights for device applications assisted by rf currents.