To understand the dynamic magnetic properties and its relationship to ultrafast field sensing, we performed micromagnetic simulations on actual MgO-based magnetic tunneling junction (MTJ) structures. The results indicate that an MTJ with a larger aspect ratio yields a smaller response time under a sudden change of an external magnetic field. Such an effect is mainly due to the coherent rotation from the central cores inside the junction element. Damping coefficient is shown to play an important role in ultrafast sensing and the optimal value need to be a few times larger than typical values found in common ferromagnetically soft materials. Our calculations further show that the response time can be reduced by increasing the free layer thickness and/or its saturation magnetization. Finally, we have obtained the dependence of intrinsic resonance frequency on the sensor size while keeping the same aspect ratio.
Skip Nav Destination
Research Article| June 30 2011
Ultrafast magnetization dynamics in magnetic tunneling junctions
Xiaojing Zou, Gang Xiao; Ultrafast magnetization dynamics in magnetic tunneling junctions. Appl. Phys. Lett. 27 June 2011; 98 (26): 263506. https://doi.org/10.1063/1.3605557
Download citation file: