Magnetic recording write head with selected write gap current direction for minimization of cross-track interference
A magnetic recording write head has an electrically-conductive structure in the write gap between the write pole and the trailing shield and electrical circuitry for directing current through the write gap. The current through the electrically-conductive structure generates a circular Ampere field which, at the disk-facing end of the write pole, is substantially parallel to the disk-facing end of the write pole. The electrically-conductive structure in the write gap may be a STO or an electrically-conductive layer that is not part of a STO. The current direction through the electrically-conductive structure in the write gap is selected so that the generated Ampere field at the write pole end is in substantially the same direction as the magnetization direction of the write head side shields, which has been discovered to result in minimization of cross-track interference.
1. A magnetic recording write head, the write head comprising:
a write pole having an end disposed at a gas bearing surface (GBS);
a trailing shield, the write pole and trailing shield spaced apart to define a write gap;
an electrically-conductive structure disposed in the write gap, wherein the magnetic recording write head is configured to direct current through the electrically-conductive structure to generate an Ampere field; and
a pair of side shields, the side shields being disposed on opposite sides of the write pole on a cross-track line, the side shields having a magnetization in a substantially cross-track direction, wherein the generated Ampere field is in substantially the same direction as the magnetization of the side shields.
2. The head of claim 1 wherein the electrically-conductive structure comprises an electrically-conductive layer.
3. The head of claim 2 wherein the conductive layer comprises a material selected from Cu, Au, Ru, Cr, W, Mo, Pt, Rh and alloys thereof.
4. The head of claim 1 wherein the electrically-conductive structure comprises a spin-torque oscillator (STO).
5. The head of claim 4 wherein the STO is configured to provide an oscillatory auxiliary magnetic field in the presence of current through the STO, and further comprising electrical circuitry connected to the write pole and the trailing shield.
6. The head of claim 4 wherein the STO comprises a ferromagnetic field generation layer (FGL), a ferromagnetic spin-polarizing layer (SPL), and a nonmagnetic spacer layer between the FGL and SPL, and further comprising electrical circuitry connected to the write pole and the trailing shield.
7. The head of claim 6 wherein the FGL is configured to provide microwave-assisted magnetic recording to a recording layer in the presence of current through the STO.
8. The head of claim 1 further comprising an electrically conductive coil coupled to the write pole, the write pole configured to generate a magnetic write field in the presence of electrical write current through the coil.
9. The head of claim 8 further comprising electrical circuitry connected to the write pole and the trailing shield for directing current through the electrically-conductive structure in the write gap.
10. A magnetic recording disk drive comprising:
the write head of claim 9 ; and
a rotatable magnetic recording disk having a perpendicular magnetic recording layer with data tracks.
11. A magnetic recording disk drive write head for magnetizing regions in data tracks of a magnetic recording layer on a disk, the write head being formed on a slider having a gas-bearing surface (GBS), the write head comprising:
a write pole having an end substantially at the GBS;
a trailing shield having an end substantially at the GBS, the write pole end and trailing shield end being spaced apart to define a write gap, wherein an along-the-track line on the write head is a line substantially orthogonal to the gap and substantially parallel to the GBS, and a cross-track line on the write head is a line substantially orthogonal to the along-the-track line and substantially parallel to the GBS;
an electrically-conductive layer in the write gap, wherein there is no spin-torque oscillator (STO) in the write gap;
a pair of ferromagnetic side shields, the side shields disposed on opposite sides of the write pole end on the cross-track line, the side shields having a magnetization in a substantially cross-track direction; and
an electrical circuit coupled to the write pole and the trailing shield for directing current through the conductive layer in the write gap to generate an Ampere field in substantially the same direction as the magnetization of the side shields.
12. The head of claim 11 wherein the electrically-conductive layer comprises a material selected from Cu, Au, Ru, Cr, W, Mo, Pt, Rh and alloys thereof.
13. The head of claim 11 further comprising a return pole formed of ferromagnetic electrically-conductive material and coupled to the trailing shield, and an electrical coil coupled to the write pole and return pole for generating a magnetic write field in the write pole.
14. A magnetic recording disk drive comprising:
the write head of claim 13 ; and
a rotatable magnetic recording disk having a perpendicular magnetic recording layer with data tracks.
15. A magnetic recording disk drive write head for magnetizing regions in data tracks of a magnetic recording layer on a disk, the write head being formed on a slider having a gas-bearing surface (GBS), the write head comprising:
a write pole having an end substantially at the GBS;
a trailing shield having an end substantially at the GBS, the write pole end and trailing shield end being spaced apart to define a write gap, wherein an along-the-track line on the write head is a line substantially orthogonal to the gap and substantially parallel to the GBS, and a cross-track line on the write head is a line substantially orthogonal to the along-the-track line and substantially parallel to the GBS;
a spin-torque oscillator (STO) in the write gap;
a pair of ferromagnetic side shields, the side shields disposed on opposite sides of the write pole end on the cross-track line, the side shields having a magnetization in a substantially cross-track direction; and
an electrical circuit coupled to the write pole and the trailing shield for directing current through the STO in the write gap to generate an Ampere field in substantially the same direction as the magnetization of the side shields.
16. The head of claim 15 wherein the STO is configured to provide an oscillatory auxiliary magnetic field in the presence of current through the STO.
17. The head of claim 15 wherein the STO comprises a ferromagnetic field generation layer (FGL), a ferromagnetic spin-polarizing layer (SPL), and a nonmagnetic spacer layer between the FGL and SPL.
18. The head of claim 17 wherein the FGL is configured to provide microwave-assisted magnetic recording to the recording layer in the presence of current through the STO.
19. The head of claim 15 further comprising a return pole formed of ferromagnetic electrically-conductive material and coupled to the trailing shield, and an electrical coil coupled to the write pole and return pole for generating a magnetic write field in the write pole.
20. A magnetic recording disk drive comprising:
the write head of claim 19 ; and
a rotatable magnetic recording disk having a perpendicular magnetic recording layer with data tracks.