Magnetic recording head, magnetic head assembly, magnetic recording apparatus, and magnetic recording method

• US 20100134922A1
• Filed: 11/30/2009
• Published: 06/03/2010
• Est. Priority Date: 11/28/2008
• Status: Active Grant

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Iwasaki, Hitoshi, Yamada, Kenichiro, Takagishi, Masayuki
• Granted Patent: US 8,767,346 B2
• Time in Patent Office: Days
• US Class Current: 360/123.10
• CPC Class Codes: G11B 20/10222 clock-related aspects, e.g. phase or frequency adjustment or bit synchronisation dedicated sync patterns in the modulation code G11B20/1403
• CPC Class Codes: G11B 2005/001 Controlling recording characteristics of record carriers or transducing characteristics of transducers by means not being part of their structure
• CPC Class Codes: G11B 5/09 Digital recording
• CPC Class Codes: G11B 5/1278 specially adapted for magnetisations perpendicular to the surface of the record carrier
• CPC Class Codes: G11B 5/3123 by using special coil configurations or conductors
• CPC Class Codes: G11B 5/3133 including layers not usually being a part of the electromagnetic transducer structure and providing additional features, e.g. for improving heat radiation, reduction of power dissipation, adaptations for measurement or indication of gap depth or other properties of the structure G11B5/3106 takes precedence
• CPC Class Codes: G11B 5/35 having vibrating elements

Abstract

A magnetic recording head includes a first magnetic pole, a second magnetic pole, a spin torque oscillator, a first coil, a second coil, and a third coil. The first magnetic pole applies a recording magnetic field to a magnetic recording medium. The second magnetic pole is provided parallel to the first magnetic pole. At least a portion of the spin torque oscillator is provided between the first magnetic pole and the second magnetic pole. The first coil magnetizes the first magnetic pole. A current is passed through the second coil independently of the first coil. A current is passed through the third coil independently of both the first coil and the second coil.

Claims

1. A magnetic recording head, comprising:

a first magnetic pole to apply a recording magnetic field to a magnetic recording medium;

a second magnetic pole provided parallel to the first magnetic pole;

a spin torque oscillator at least of which portion is provided between the first magnetic pole and the second magnetic pole;

a first coil to magnetize the first magnetic pole;

a second coil through which a current is passed independently of the first coil; and

a third coil through which a current is passed independently of both the first coil and the second coil.

2. The head according to claim 1, wherein the second magnetic pole is more recessed than the first magnetic pole with reference to the magnetic recording medium.

4. The head according to claim 1 further comprising a side shield provided so that the side shield faces at least one of side surfaces of the first magnetic pole and the spin torque oscillator.

5. The head according to claim 1, wherein the spin torque oscillator comprising:

a first magnetic layer having a coercivity smaller than a magnetic field applied from the first magnetic pole;

a second magnetic layer having a coercivity smaller than a magnetic field applied from the first magnetic pole; and

a nonmagnetic intermediate layer to be provided between the first magnetic layer and the second magnetic layer.

3. A magnetic recording head, comprising:

a first magnetic pole to apply a recording magnetic field to a magnetic recording medium;

a spin torque oscillator provided parallel to the first magnetic pole;

a first coil to magnetize the first magnetic pole; and

a second coil to pass a current independently of the first coil.

6. A magnetic head assembly, comprising:

a magnetic recording head including;

a first magnetic pole to apply a recording magnetic field to a magnetic recording medium;

a second magnetic pole provided parallel to the first magnetic pole;

a spin torque oscillator at least of which portion is provided between the first magnetic pole and the second magnetic pole;

a first coil to magnetize the first magnetic pole;

a second coil through which a current is passed independently of the first coil; and

a third coil through which a current is passed independently of both the first coil and the second coil,

a head slider mounting the magnetic recording head;

a suspension mounting the head slider onto an end thereof; and

an actuator arm connected to the other end of the suspension.

7. A magnetic recording apparatus, comprising:

a magnetic recording medium;

a magnetic head assembly including;

a magnetic recording head including;

a first magnetic pole to apply a recording magnetic field to the magnetic recording medium;

a second magnetic pole provided parallel to the first magnetic pole and;

a spin torque oscillator at least of which portion is provided between the first magnetic pole and the second magnetic pole;

a first coil to magnetize the first magnetic pole;

a second coil through which a current is passed independently of the first coil; and

a third coil through which a current is passed independently of both the first coil and the second coil,

a head slider mounting the magnetic recording head;

a suspension mounting the head slider onto an end thereof; and

an actuator arm connected to the other end of the suspension,

a signal processor to write and read a signal on the magnetic recording medium by using the magnetic recording head.

8. The apparatus according to claim 7,

wherein

the signal processor including:

a first current circuit to supply a recording current to the first coil, the recording current including a recording signal to be recorded on the magnetic recording medium; and

a second current circuit to supply a modulating current to the second coil.

9. The apparatus according to claim 8,

wherein

the second current circuit supplies the modulating current to the second coil;

and

wherein

the modulating current includes either one of a signal changing at a frequency higher than that of the recording signal and a signal having the same frequency as the recording signal to change an absolute value thereof in one cycle.

10. The apparatus according to claim 8, further comprising:

a third current circuit to pass a modulating current through the third coil, the modulating current changing coincident with a polarity reversal of the recording current; and

a recording signal circuit to supply an electric signal to the first current circuit, the electric signal including a recording signal to be recorded on the magnetic recording medium,

wherein

the third current circuit supplies the modulating current based on the electric signal.

11. The apparatus according to claim 10, wherein the signal processing portion further includes a phase adjustment circuit to advance or delay the controlling current more than a polarity reversal of the recording current.

12. A magnetic recording apparatus, comprising:

a magnetic recording medium;

a magnetic recording head including;

a first magnetic pole to apply a recording magnetic field to the magnetic recording medium;

a second magnetic pole provided parallel to the first magnetic pole;

a spin torque oscillator at least of which portion is provided between the first magnetic pole and the second magnetic pole;

a first coil to magnetize the first magnetic pole; and

a second coil through which a current is passed independently of the first coil, and

a signal processor to write and read a signal on the magnetic recording medium by using the magnetic recording head, the signal processor including;

a first current circuit to supply a recording current to the first coil, the recording current including a recording signal to be recorded on the magnetic recording medium; and

a second current circuit to supply a modulating current to the second coil,

wherein

the modulating current includes either one of a signal changing at a frequency higher than that of the recording signal and a signal having the same frequency as the recording signal to change an absolute value thereof in one cycle.

13. The apparatus according to claim 12,

wherein

the second current circuit includes a modulation signal current circuit and an controlling current circuit;

wherein

the modulation signal current circuit supplies a current including either one of a signal changing at a frequency higher than that of the recording signal and a signal having the same frequency as the recording signal to change an absolute value thereof in one cycle; and

wherein

the controlling current circuit supplies an controlling current changing coincident with a polarity reversal of the recording current.

14. The apparatus according to claim 12,

wherein

the singal processing portion further includes a recording signal circuit to supply an electric signal to the first current circuit;

wherein

the electric signal includes a signal to be recorded on the magnetic recording medium; and

wherein

the second current circuit supplies the controlling current based on the electric signal.

15. A magnetic recording apparatus, comprising:

a magnetic recording medium;

a magnetic recording head including;

a first magnetic pole to apply a recording magnetic field to the magnetic recording medium;

a spin torque oscillator arranged parallel to the first magnetic pole;

a first coil to magnetize the first magnetic pole; and

a signal processor to write and read a signal on the magnetic recording medium by using the magnetic recording head, the signal processor including a first current circuit to supply a recording current to the first coil, the recording current including a recording signal to be recorded on the magnetic recording medium,

wherein

the recording current includes either one of a signal changing at a frequency higher than that of the recording signal, and a signal having the same frequency as the recording signal to change an absolute value thereof in one cycle.

16. The apparatus according to claim 15,

wherein

the first current circuit includes a recording signal current circuit and a modulation signal current circuit;

wherein

the recording signal current circuit supplies a recording current including the recording signal; and

wherein

the modulation signal current circuit supplies either one of a signal changing at a frequency higher than that of the recording signal, and a signal having the same frequency as the recording signal to change an absolute value thereof in one cycle.

17. The apparatus according to claim 15,

wherein

a frequency of the signal changing at a frequency higher than that of the recording signal is not less than a value;

and

wherein

the value is a relative velocity between the magnetic recording head and the magnetic recording medium divided by an average size of magnetic grains included in the magnetic recording medium.

18. The apparatus according to claim 15, wherein the magnetic recording medium is a discrete track medium of which recording tracks adjacent to each other are formed to be separated by a nonmagnetic member.

19. The apparatus according to claim 15, wherein the magnetic recording medium is a discrete track medium of which recording magnetic bits are isolated by a nonmagnetic member to align regularly.

20. A method for recording information onto a magnetic recording medium, comprising:

recording information onto the magnetic recording medium while applying a magnetic field to a spin torque oscillator arranged near a magnetic pole to record information onto the magnetic recording medium, the magnetic field including either one of a first signal changing at a frequency higher than that of a recording signal to be recorded on the magnetic recording medium and a second signal having the same frequency as the recording signal to change an absolute value thereof in one cycle.