Implementing spin torque oscillator power-on oscillation checker for microwave-assisted magnetic recording hard disk drives

摘要

A method, apparatus, and system are provided for implementing a power-on spin-torque oscillator (STO) oscillation checker to monitor STO resistance to identify STO oscillation with microwave assisted magnetic recording (MAMR) hard disk drives (HDDs). An amplitude modulated write coil drive current is applied to the write coil in the presence of a DC bias current applied to the STO. The amplitude modulated write coil drive current modulates the STO resistance monitored using an amplifier circuit to identify STO oscillation, used to ensure stable MAMR HDD write operation.

主权项

1. A method for implementing a spin-torque oscillator (STO) oscillation checker for microwave assisted magnetic recording (MAMR) hard disk drives (HDDs) comprising:
applying an amplitude modulated write coil current to a write coil coupled to a spin-torque oscillator (STO) at power-on and periodically during MAMR HDD operation; using an amplifier circuit coupled to the STO, monitoring STO voltage responsive to the applied amplitude modulated write coil current to identify STO resistance modulation; using said identified STO resistance modulation to identify STO oscillation; and using the identified STO oscillation to ensure stable MAMR HDD write operation.