Selective magnetization switching with microwave assistance for three-dimensional magnetic recording

Abstract

The possibility of selective magnetization switching in a three-layered stacked magnetic pillar was discussed using micromagnetic simulation that considers three-dimensional magnetic recording. Selective magnetization switching is possible with the assistance of a circularly polarized microwave field with an adequate corresponding frequency. This study demonstrates that the value of the saturation magnetization of the magnetic layers is critical in suppressing selective magnetization switching errors caused by magnetostatic fields. A relatively large saturation magnetization of up to 600 emu/cm3 in the second layer also allows successful selective magnetization switching, thus enabling three-dimensional magnetic recording. However, damping constants smaller than 0.1 for the magnetic layers are crucial in the model calculations because of the limited strength of the microwave fields applied to the stacked magnetic pillar. The leakage flux is also estimated considering a multi-bit reproducing process, where eight-digit signals are obtained depending on the magnetization states of the stacked magnetic pillar.