R&D: Systematic Evaluation of MAMR

IEEE Transactions on Magnetics has published an article written by Zengyuan Liu, Seagate Research Group, Seagate Technology, Shakopee, MN 55379 USA, Pin-Wei Huang, Fremont Research Center, Seagate Technology, Fremont, CA 94538 USA, Stephanie Hernandez, Seagate Research Group, Seagate Technology, Shakopee, MN 55379 USA, Ganping Ju, Fremont Research Center, Seagate Technology, Fremont, CA 94538 USA, and Tim Rausch , Seagate Research Group, Seagate Technology, Shakopee, MN 55379 USA

Abstract: “A micro-magnetic simulation model to evaluate microwave-assisted magnetic recording (MAMR) has been developed. Optimization of the spin torque oscillator with ac field strength, head geometry, and oscillating frequency is reported. Realistic recording conditions, including media properties and head parameters, are implemented to show the benefits and challenges of MAMR. We found the out-of-plane component of the ac magnetic field causes erasure when medium anisotropy is low for the system during the writing process even while ferromagnetic resonance is helping switching the recording media grains. The signal-to-noise ratio (SNR) of MAMR is calculated using ensemble waveform analysis with a pseudorandom bit sequence which mimics real user data. The SNR is compared under different recording media anisotropy field while maintaining the same linear density.”