Magnetic recording head including spatially-pumped spin wave mode writer
View Patent ↗The present invention provides magnetic recording heads which utilize higher order excitations of dynamic magnetization to increase frequency without the necessity of biasing the write yoke. In accordance with the present invention, the size and placement of current-carrying microstrip waveguide(s) and write pole(s) are controlled in order to generate spin wave write modes. During writing operations, the magnetization is driven into higher order spatial spin wave modes.
1. A magnetic writer for use with a magnetic storage medium, comprising:
at least one write pole; and
at least one microstrip structured and arranged to generate magnetization in the at least one write pole comprising at least one spin wave mode comprising a spatially non-uniform magnetization pattern along a length of the write pole.
2. The magnetic writer of claim 1 , wherein the non-uniform magnetization pattern of the at least one spin wave mode substantially corresponds to the formula Sin(nπy/L+Φ), where n is a mode index and is 1 or higher, L is the length of the write pole, y is a position along the length L of the write pole, and Φ is a phase factor determined by boundary conditions of the write pole.
3. The magnetic writer of claim 2 , wherein n is from 1 to 5.
4. The magnetic writer of claim 2 , wherein n is from 2 to 4.
5. The magnetic writer of claim 2 , wherein n=1.
6. The magnetic writer of claim 2 , wherein n=2.
7. The magnetic writer of claim 2 , wherein n=3.
8. The magnetic writer of claim 2 , wherein n=4.
9. The magnetic writer of claim 1 , wherein the writer comprises a single microstrip.
10. The magnetic writer of claim 1 , wherein the writer comprises two microstrips.
11. The magnetic writer of claim 1 , wherein the writer comprises a single write pole.
12. The magnetic writer of claim 1 , wherein the writer comprises two write poles.
13. The magnetic writer of claim 12 , wherein the two write poles are connected by a yoke.
14. The magnetic writer of claim 1 , wherein the writer is a longitudinal writer.
15. The magnetic writer of claim 1 , wherein the writer is a perpendicular writer.
16. The magnetic writer of claim 1 , wherein the at least one microstrip is within 100 nm of an air bearing surface of the writer.
17. The magnetic writer of claim 1 , wherein the at least one microstrip has a width W, the at least one write pole has a length L, and the ratio of W:L is from about 1:2 to about 1:5.
18. The magnetic writer of claim 17 , wherein the ratio of W:L is about 1:2 and the non-uniform magnetization pattern of the at least one spin wave mode substantially corresponds to the formula Sin (nπy/L+Φ), where n is a mode index and is equal to 1, L is the length of the write pole, y is a position along the length L of the write pole, and Φ is a phase factor determined by boundary conditions of the write pole.
19. The magnetic writer of claim 18 , wherein the writer comprises a single microstrip located adjacent to a tip of the write pole.
20. The magnetic writer of claim 17 , wherein the ratio of W:L is about 1:3 and the non-uniform magnetization pattern of the at least one spin wave mode substantially corresponds to the formula Sin(nπy/L+Φ), where n is a mode index and is equal to 2, L is the length of the write pole, y is a position along the length L of the write pole, and Φ is a phase factor determined by boundary conditions of the write pole.
21. The magnetic writer of claim 20 , wherein the writer comprises a single microstrip located substantially mid-way along the length L of the write pole.
22. The magnetic writer of claim 20 , wherein the writer comprises two microstrips, one of which is located adjacent to a tip of the at least one write pole and the other of which is located adjacent to an opposite end of the at least one write pole.
23. The magnetic writer of claim 17 , wherein the ratio of W:L is about 1:4 and the non-uniform magnetization pattern of the at least one spin wave mode substantially corresponds to the formula Sin(nπy/L+Φ), where n is a mode index and is equal to 3, L is the length of the write pole, y is a position along the length L of the write pole, and Φ is a phase factor determined by boundary conditions of the write pole.
24. The magnetic writer of claim 23 , wherein the writer comprises two microstrips located adjacent to each other near the middle of the length L of the write pole.
25. The magnetic writer of claim 24 , wherein current is applied in opposite directions through the microstrips.
26. The magnetic writer of claim 17 , wherein the ratio of W:L is about 1:5 and the non-uniform magnetization pattern of the at least one spin wave mode substantially corresponds to the formula Sin(nπy/L+Φ), where n is a mode index and is equal to 4, L is the length of the write pole, y is a position along the length L of the write pole, and Φ is a phase factor determined by boundary conditions of the write pole.
27. The magnetic writer of claim 26 , wherein the writer comprises two microstrips, one of which is located at a two-fifths position along the length L of the write pole and the other of which is located at a four-fifths position along the length L of the write pole.
28. The magnetic writer of claim 27 , wherein current is applied in the same direction through the microstrips.
29. A magnetic writer for use with a magnetic storage medium, comprising:
at least one write pole in proximity to the magnetic storage medium; and
means for generating magnetization in the at least one write pole comprising at least one spin wave mode comprising a spatially non-uniform magnetization pattern along a length of the write pole to thereby apply a magnetic write field to the magnetic storage medium.
30. A method of applying a magnetic write field to a magnetic storage medium, comprising:
providing at least one write pole in proximity to the magnetic storage medium; and
generating magnetization in the at least one write pole comprising at least one spin wave mode comprising a spatially non-uniform magnetization pattern along a length of the write pole to thereby apply the magnetic write field to the magnetic storage medium.