Increasing AC-field frequency in microwave-assisted magnetic recording

Hard disk drives (HDDs) have been investigated to determine how to increase their areal recording density. Recently, however, HDDs have been having problems with noise, thermal fluctuations, and writability simultaneously, commonly known as a trilemma. Microwave-assisted magnetic recording (MAMR) is a promising recording method to solve this trilemma [1-4]. In MAMR, a spin torque oscillator (STO) is placed between a conventional write head and a trailing shield. Because the AC field from the STO decreases the switching magnetic fields of the medium, the writability can be improved. As a result, the trilemma can be solved. Therefore, a high frequency AC field with strong amplitude is needed. In this study, we examined methods to increase the AC-field frequency by using a micro-magnetic simulator that takes into account magnetic interactions between the write head, the medium, and the STO.