Implementing spin torque oscillator power-on oscillation checker for microwave-assisted magnetic recording hard disk drives
AssigneeHGST Netherlands B.V.
InventorsJohn Contreras, Samir Y. Garzon, Rehan Ahmed Zakai
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Abstract
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.
Claims17
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.
An apparatus for implementing a spin-torque oscillator (STO) oscillation checker for microwave assisted magnetic recording (MAMR) hard disk drive (HDDs), comprising:
- a controller;
- at least one disk;
- said disk including a disk media for storing data;
- a spin-torque oscillator (STO) for microwave assisted magnetic recording (MAMR);
- a write coil coupled to said spin-torque oscillator (STO);
- the spin-torque oscillator (STO) oscillation checker comprising
- a current source applying an amplitude modulated write coil current to the write coil coupled to a spin-torque oscillator (STO) at power-on and periodically during MAMR HDD operation;
- an amplifier circuit coupled to the STO, monitoring STO voltage responsive to the applied amplitude modulated write coil current to identify STO resistance modulation, and using said identified STO resistance modulation to identify STO oscillation;
- and
- said controller using the identified STO oscillation to ensure stable MAMR HDD write operation.
A system for implementing a spin-torque oscillator (STO) oscillation checker comprising:
- a microwave assisted magnetic recording (MAMR) hard disk drive (HDD), said MAMR HDD comprising a controller;
- at least one disk;
- said disk including a disk media for storing data;
- a spin-torque oscillator (STO) for microwave assisted magnetic recording (MAMR);
- a write coil coupled to said spin-torque oscillator (STO);
- a Read/Write integrated circuit (IC) coupled to a slider, said slider containing said spin-torque oscillator (STO);
- and said Read/Write integrated circuit (IC) implementing the spin-torque oscillator (STO) oscillation checker;
- the spin-torque oscillator (STO) oscillation checker comprising
- a current source applying an amplitude modulated write coil current to the write coil coupled to a spin-torque oscillator (STO);
- an amplifier circuit coupled to the STO, monitoring STO voltage responsive to the applied amplitude modulated write coil current to identify STO resistance modulation, and using said identified STO resistance modulation to identify STO oscillation;
- and
- said controller using the identified STO oscillation to ensure stable MAMR HDD write operation.
Dependencies are inferred from the claim text.