Magnetic data recording system with improved servo capability for bit patterned recording
View Patent ↗A magnetic data recording system wherein the wherein adjacent track interference during writing is avoided by modulating the size of a write bubble on the magnetic media in response to a position error signal. If the position error signal indicates that the magnetic head is off-track, circuitry within the magnetic data recording system adjusts the size of the write bubble temporarily to prevent the write bubble from encroaching on a neighboring data track. This adjustment of the write bubble can be accomplished by adjusting power to the write head. Adjustment of the write bubble can also be achieved by adjusting power to a magnetic oscillator in a microwave assisted magnetic recording system (MAMR) or adjusting power to a heating element in a thermally assisted magnetic recording system.
1. A method for preventing adjacent track interference during writing, comprising:
generating a position error signal;
calculating a write current modulation based on the position error signal; and
adjusting a write current and a microwave field from a magnetic oscillator to modulate the size of a write bubble.
2. The method as in claim 1 further comprising after calculating the write current modulation, communicating the current modulation to a write driver and to curvature compensation circuitry.
3. The method as in claim 1 further comprising adjusting a down-track phase in curvature compensation circuitry.
4. A method for preventing adjacent track interference in a magnetic data recording system, comprising: generating a position error signal; and modulating a size of a write bubble based on the position error signal to avoid writing to an adjacent data track; wherein the size of the write babble is modulated by adjusting power delivered to a microwave oscillator.
5. The method as in claim 4 wherein the size of the write bubble is modulated by adjusting power delivered to a write coil of a magnetic write head.
6. The method as in claim 4 wherein the microwave oscillator is a spin torque oscillator.
7. The method as in claim 4 wherein the size of the write bubble is modulated by adjusting power to a write coil of a magnetic write head and adjusting power to the microwave oscillator.
8. The method as in claim 4 wherein the size of the write bubble is also modulated by adjusting power to a heating element.
9. The method as in claim 4 wherein the size of the write bubble is also modulated by adjusting power to a write coil of a magnetic write head and by adjusting power to a heating element.
10. A magnetic data recording system, comprising: a magnetic media having a plurality of data tracks; a slider having a magnetic read head and a magnetic write head formed thereon; an actuator connected with the slider to position the slider over a surface of the magnetic media; circuitry configured to generate a position error signal based on a signal from the read head; circuitry configured to calculate a write bubble modulation based on the position error signal; a microwave oscillator; and circuitry for adjusting power delivery to the microwave oscillator in order to modulate the write bubble based on the calculated write bubble modulation; wherein the magnetic data recording system is configured for hyper-track recording.
11. The magnetic data recording system as in claim 10 further comprising circuitry for adjusting power delivery to the magnetic write head in order to modulate the write bubble based on the calculated write bubble modulation.
12. The magnetic data recording system as in claim 10 further comprising:
a heating element; and
circuitry for adjusting power delivery to the heating element in order to modulate the write bubble based on the calculated write bubble modulation.
13. The magnetic data recording system as in claim 10 further comprising:
a heating element; and
circuitry for adjusting power delivery to the heating element and to the write head to modulate the write bubble based on the calculated write bubble modulation.
14. The magnetic data recording system as in claim 10 further comprising:
circuitry for calculating a write current modulation based on the position error signal;
circuitry for communicating the write current modulation to a write driver and to a curvature compensation circuit.
15. The magnetic data recording system as in claim 10 further comprising circuitry for adjusting a down-track phase in a curvature compensation circuit.
16. The magnetic data recording system as in claim 10 wherein the magnetic media is a bit patterned media.
17. The magnetic data recording system as in claim 10 wherein the magnetic data recording system is configured for shingled recording.