Effect of film thickness on microwave assisted switching behavior

We study the effect of magnetic film thickness t
mag
on microwave assisted switching (MAS) behavior in CoCrPt-SiO
2
granular film. Magnetization switching behaviors are evaluated by measuring the anomalous Hall effect of the granular film under microwave field application. The thermal stability factor for magnetization reversal is varied from E
0
= 85 k
B
T to 110 k
B
T by changing the film thickness t
mag
=10 nm to 15 nm. The slope of the frequency dependence of the coercivity becomes slightly gradual and the critical frequency shifts toward a few GHz higher by decreasing film thickness. Such film thickness dependencies are well explained by considering the thermal activation based on the effective energy barrier height under excitation with a microwave field.