Textured magnetic poles for magnetic writers
View Patent ↗A magnetic writer is formed with a texture on a surface of a write pole, preferably on a surface associated with the trailing edge of the writer. This texturing results in, in effect, a magnon-magnon scattering process that increases the surface damping of the pole and thus decreases the write field rise time. Rare earth elements can also be added in amounts sufficient to further increase the damping.
1. A magnetic writer including:
a magnetic shield;
a pole piece with a textured surface, wherein the textured surface is perpendicular to a magnetic recording medium and is located only at a tip of the pole piece, and wherein the textured surface is a trailing surface of the tip with respect to a direction of motion of the magnetic recording medium, and wherein the textured surface is adjacent a gap between the pole piece and the magnetic shield, which is opposite the trailing surface of the tip; and
an electrical conductor through which currents are passed to effect changes in a magnetic field produced at the tip,
wherein the textured surface comprises a series of grooves parallel to the magnetic recording medium and perpendicular to the direction of motion of the medium, and
wherein the grooves have widths in the range of 10 nm to 50 nm.
2. The writer of claim 1 wherein the textured surface includes additions of rare earth elements.
3. The writer of claim 2 wherein the rare earth elements are added to a concentration between 0.5% and 5%.
4. The writer of claim 1 wherein the grooves have depths of 0.5 to 1.5 of the widths.
5. The writer of claim 1 wherein the texture of the textured surface has a random configuration.
6. The writer of claim 1 further including a ferromagnetic film that extends over the textured surface, the film having rare earth additions.
7. The writer of claim 1 , wherein the pole piece comprises a laminated pole piece and the textured surface is located at only a tip of the laminated pole piece.
8. A digital magnetic recording system comprising:
a magnetic recording medium; and
a magnetic writer for applying a magnetic field to the recording medium, the writer including:
a magnetic shield;
a pole piece, the pole piece having a textured surface, wherein the textured surface is perpendicular to the magnetic recording medium and is located only at a tip of the pole piece, and wherein the textured surface is a trailing surface of the tip with respect to a direction of motion of the magnetic recording medium, and wherein the textured surface is adjacent a gap between the pole piece and the magnetic shield, which is opposite the trailing surface of the tip; and
an electrical conductor through which currents are passed to effect changes in a magnetic field produced at the tip,
wherein the textured surface comprises a series of grooves parallel to the magnetic recording medium and perpendicular to the direction of motion of the medium, and
wherein the grooves have widths in the range of 10 nm to 50 nm.
9. A magnetic writer including:
a magnetic shield;
a pole piece with a textured surface that is located at at least a tip of the pole piece, wherein the textured surface is a trailing surface of the tip with respect to a direction of motion of a magnetic recording medium, and wherein the textured surface is adjacent a gap between the pole piece and the magnetic shield, which is opposite the trailing surface of the tip, and wherein the textured surface comprises a series of grooves parallel to the magnetic recording medium and perpendicular to the direction of motion of the medium; and
an electrical conductor through which currents are passed to effect changes in a magnetic field produced at the tip,
wherein the grooves have widths in the range of 10 nm to 50 nm.
10. The writer of claim 9 wherein the grooves have depths of 0.5 to 1.5 of the widths.
11. A magnetic writer including:
a magnetic shield;
a pole piece with a textured surface, wherein the textured surface is perpendicular to a magnetic recording medium and is located only at a tip of the pole piece, and wherein the textured surface is adjacent a gap between the pole piece and the magnetic shield, which is opposite a trailing surface of the tip; and
an electrical conductor through which currents are passed to effect changes in a magnetic field produced at the tip,
wherein the textured surface comprises a series of grooves parallel to the magnetic recording medium and perpendicular to a direction of motion of the medium, and
wherein the grooves have widths in the range of 10 nm to 50 nm.
12. The writer of claim 11 wherein the textured surface includes additions of rare earth elements.