Methods and devices for spin torque oscillator control and monitoring
First Claim
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1. An apparatus for microwave-assisted magnetic recording, the apparatus comprising:
- a magnetic write head operable to write data to a magnetic storage medium;
a spin-torque microwave oscillator coupled to the magnetic write head and operable to provide microwave radiation to the magnetic storage medium; and
a driver circuit in communication with the magnetic write head, the driver circuit operable to dynamically modulate bias current provided to the spin-torque microwave oscillator in sympathy with data being written to the magnetic storage medium by the magnetic write head,wherein the driver circuit reduces the bias current provided to the spin-torque microwave oscillator during write data no-transition runs having a length longer than a predetermined length.
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Abstract
An apparatus for microwave-assisted magnetic recording includes a magnetic write head operable to write data to a magnetic storage medium. The apparatus includes a spin-torque microwave oscillator coupled to the magnetic write head and operable to provide microwave radiation to the magnetic storage medium. The apparatus includes a driver circuit in communication with the magnetic write head. The driver circuit is operable to dynamically modulate bias current provided to the spin-torque microwave oscillator in sympathy with data being written to the magnetic storage medium by the magnetic write head.
82 Citations
20 Claims
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1. An apparatus for microwave-assisted magnetic recording, the apparatus comprising:
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a magnetic write head operable to write data to a magnetic storage medium; a spin-torque microwave oscillator coupled to the magnetic write head and operable to provide microwave radiation to the magnetic storage medium; and a driver circuit in communication with the magnetic write head, the driver circuit operable to dynamically modulate bias current provided to the spin-torque microwave oscillator in sympathy with data being written to the magnetic storage medium by the magnetic write head, wherein the driver circuit reduces the bias current provided to the spin-torque microwave oscillator during write data no-transition runs having a length longer than a predetermined length. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method for recording data, the method comprising:
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receiving a signal indicative of data to be written to a magnetic storage medium; generating a first control signal that causes a magnetic write head to write the data to the magnetic storage medium; generating a second control signal that causes a spin-torque microwave oscillator to provide microwave radiation to the magnetic storage medium; dynamically adjusting the second control signal to compensate for changes in the first control signal; measuring a frequency of radiation provided by the spin-torque microwave oscillator; and in response to the measured frequency of radiation, adjusting the second control signal. - View Dependent Claims (11, 12, 13, 14, 15)
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16. A magnetic recording system, comprising:
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a write channel; a preamplifier receiving a signal from the write channel that is indicative of data to be written to a magnetic recording medium; a write head that generates a magnetic field based on a first driver signal received from the preamplifier, the magnetic field causing the data to be written to the magnetic recording medium; and an oscillator that generates microwave radiation based on a second driver signal received from the preamplifier, the second driver signal being dynamically modulated in sympathy with the first driver signal, wherein the oscillator comprises a spin-torque microwave oscillator, wherein the second driver signal comprises a bias current provided to the spin-torque microwave oscillator, and wherein the preamplifier is operable to dynamically modulate the second driver signal by performing one or more of the following operations; (i) elevating the bias current provided to the spin-torque microwave oscillator at a transition point of a write field applied by the write head; (ii) lowering the bias current provided to the spin-torque microwave oscillator in anticipation of a transition of the write field applied by the write head; (iii) reducing the bias current provided to the spin-torque microwave oscillator during write data no-transition runs having a length longer than a predetermined length; and (iv) adjusting the bias current to cause the spin-torque oscillator to change a frequency of the radiation generated thereby toward a determined frequency. - View Dependent Claims (17, 18, 19, 20)
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Specification