The spatial variation of coercivity on patterned magneto-optical (MO) materials has been studied with a Kerr microscope. Our results show that the coercivity values on arrays made by holes are larger than those observed on the land regions. In contrast with nonpatterned MO media, which present a sharp Gaussian-like distribution, the coercivity distribution in the patterned material is much wider and shows an exponential-type distribution. This article maps the spatial variation of the coercivity on patterned magnetic materials with a spatial resolution of 0.1×0.1 μm2.
We have measured current-induced magnetization switching for MgO-based tunnel junctions with different current amplitudes and pulse durations at room temperature. The pulse widths ranged from 50μsto1ms and the current ratios J∕JC0 ranged from 0.4 to 0.97 (JC0 is the intrinsic critical current density). The results showed that the model of thermal assisted spin-transfer switching works well for the range of low to medium current ratio. However, for high current ratio, the switching probability did not fit the simple exponential function but grew with the current ratio linearly. The corresponding values of energy barrier as the current ratio approaches to unity indicated that thermal activation may still play an important role in magnetization switching.
In our previous studies, we indicated that the coercivity of patterned magneto-optical thin film is quite different from nonpatterned samples. However, we only compared the hysteresis loop bulk measurements of the samples. In this study, we measured the microhysteresis curves at an arbitrary position while coercivity distribution was mapped, and observed submicron images of the remnant state of domain reversal patterns. The spatial variations of the coercivity over several depths of hole arrays barrier on patterned film will be reported.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.