A New Dual FGL STO for MAMR

Abstract

This article discusses a micromagnetic analysis of spin-torque oscillators (STOs) with two field generation layers (FGLs) (dual FGL STO) for use in microwave-assisted magnetic recording (MAMR). Dual FGL STOs have superior characteristics with regard to stable oscillation, especially when integrated into the write head gap, due to antiferromagnetic coupling between the two FGLs. The structure and materials, however, can be complicated. Our new dual FGL STO has a simpler structure, composed of FGL/soft magnetic material (SMM)/FGL. In addition, because the oscillation frequency changes with the current density injected into the STO, it is suitable for dual-layer recording. Recording simulations showed that the STO had a high signal-to-noise ratio (SNR)/track width, compared with a dual FGL STO without the SMM layer.