Magnetic writer having a gradient in saturation magnetization of the shields and return pole
A method and system provide a magnetic transducer. The transducer includes a main pole, a side gap, at least one coil, a side shield and at least one of a leading shield, a trailing shield and a return pole. The coil(s) are configured to energize the main pole. The side gap is between the main pole and the side shield. The main pole is between the leading shield and the trailing shield. The trailing shield is between the main pole and the return pole. The side shield is between the leading shield and the trailing shield. At least one of the leading shield, the trailing shield and the return pole have a gradient in saturation magnetization such that the saturation magnetization varies in a down track direction.
1. A magnetic recording transducer having air-bearing surface (ABS) comprising:
a main pole having a leading surface and a trailing surface;
a side gap;
at least one coil configured to energize the main pole;
a side shield, the side gap residing between the side shield and the main pole; and
at least one of a leading shield, a trailing shield and a return pole, the main pole being between the leading shield and the trailing shield, the trailing shield being between the main pole and the return pole, the side shield being between the leading shield and the trailing shield, the at least one of the leading shield, the trailing shield and the return pole having a gradient in a saturation magnetization such that the saturation magnetization decreases with increasing distance from the main pole in a down track direction, such that the gradient is completely across the at least one of the leading shield, the trailing shield and the return pole in a cross-track direction perpendicular to the down track direction and such that the at least one of the leading shield, the trailing shield and the return pole have at least three different saturation magnetizations.
2. The magnetic recording transducer of claim 1 wherein the at least one of the leading shield, the trailing shield and the return pole has a first portion and a second portion, the first portion being between the second portion and the main pole, the first portion having a first saturation magnetization, the second portion having a second saturation magnetization that is substantially constant, the first saturation magnetization having at least a portion of the gradient in the saturation magnetization.
3. The magnetic recording transducer of claim 2 wherein an other of the at least the leading shield, trailing shield and return pole has an additional gradient in an additional saturation magnetization such that the additional saturation magnetization decreases in the down track direction.
4. The magnetic recording transducer of claim 3 wherein the leading shield has the gradient in the saturation magnetization and the return pole has the additional gradient in the additional saturation magnetization.
5. The magnetic recording transducer of claim 3 wherein the leading shield has the gradient in the saturation magnetization and the trailing shield has the additional gradient in the additional saturation magnetization.
6. The magnetic recording transducer of claim 1 wherein the at least one of the leading shield, the trailing shield and the return pole includes a plurality of layers having a plurality of saturation magnetizations forming the gradient in the saturation magnetization, the plurality of layers including at least three layers, each of the plurality of layers extending completely across the at least one of the leading shield, the trailing shield and the return pole in the cross-track direction, such that the leading shield has a first minimum saturation magnetization of 1.0 T furthest from the main pole in the down track direction and a first maximum saturation magnetization of not more than 2.0 T closest to the main pole in the down track direction if the leading shield has the gradient, the trailing shield has a second minimum saturation magnetization of 1.6 T furthest from the main pole in the down track direction and a second maximum saturation magnetization of not more than 2.0 T closest to the main pole in the down track direction if the trailing shield has the gradient, and the return pole has a third minimum saturation magnetization of 1.6 T furthest from the main pole in the down track direction and a third maximum saturation magnetization of not more than 2.0 T closest to the main pole in the down track direction if the return pole has the gradient.
7. The magnetic recording transducer of claim 1 wherein the leading shield has the gradient in the saturation magnetization.
8. The magnetic recording transducer of claim 1 wherein the trailing shield has the gradient in the saturation magnetization.
9. The magnetic recording transducer of claim 1 wherein the return pole has the gradient in the saturation magnetization.
10. The magnetic recording transducer of claim 1 wherein the gradient in the saturation magnetization is selected from a linear gradient, a piecewise linear gradient, stepped and a smooth curve gradient.
11. The magnetic recording transducer of claim 1 wherein the side shield has a side shield saturation magnetization and the gradient is configured such that the at least one of the leading shield, the trailing shield and the return pole has the side shield saturation magnetization at a surface closest to the side shield.
12. The magnetic recording transducer of claim 1 wherein the side shield and the leading shield share a first interface, the side shield and the trailing shield share a second interface and the trailing shield and the return pole share a third interface, and wherein at least one of the side shield and the leading shield have first matching saturation magnetizations at the first interface, the side shield and the trailing shield have second matching saturation magnetizations at the second interface and the trailing shield and the return pole have third matching saturation magnetizations at the third interface.
13. A data storage device comprising:
a media;
a slider including a magnetic recording transducer having an air-bearing surface (ABS), a main pole, a side gap, at least one coil configured to energize the main pole, a side shield and at least one of a leading shield, a trailing shield and a return pole, the side gap being between the main pole and the side shield, the main pole being between the leading shield and the trailing shield, the side gap residing between the side shield and the main pole, the trailing shield being between the main pole and the return pole, the side shield being between the leading shield and the trailing shield, the at least one of the leading shield, the trailing shield and the return pole having a gradient in a saturation magnetization such that the saturation magnetization decreases with increasing distance from the main pole in a down track direction, such that the gradient is completely across the at least one of the leading shield, the trailing shield and the return pole in a cross-track direction perpendicular to the down track direction and such that the at least one of the leading shield, the trailing shield and the return pole have at least three different saturation magnetizations.
14. A method for providing a magnetic transducer having air-bearing surface (ABS) comprising:
providing a main pole, a portion of the main pole residing at the ABS;
providing a side gap;
providing at least one coil for energizing the main pole; and
providing a side shield, the side gap residing between the side shield and the main pole; and
providing at least one of a leading shield, a trailing shield and a return pole, the main pole being between the leading shield and the trailing shield, the trailing shield being between the main pole and the return pole, the side shield being between the leading shield and the trailing shield, the at least one of the leading shield, the trailing shield and the return pole having a gradient in a saturation magnetization such that the saturation magnetization decreases with increasing distance from the main pole in a down track direction, such that the gradient is completely across the at least one of the leading shield, the trailing shield and the return pole in a cross-track direction perpendicular to the down track direction and such that the at least one of the leading shield, the trailing shield and the return pole have at least three different saturation magnetizations.
15. The method of claim 14 wherein the step of providing the at least one of the leading shield, the trailing shield and the return pole further includes:
providing a first portion of the at least one of the leading shield, the trailing shield and the return pole; and
providing a second portion of the at least one of the leading shield, the trailing shield and the return pole, the first portion being between the second portion and the main pole, the first portion having a first saturation magnetization, the second portion having a second saturation magnetization that is substantially constant, the first saturation magnetization having at least a portion of the gradient in the saturation magnetization.
16. The method of claim 15 wherein the step of providing the first portion further includes:
plating a first layer of the first portion at a first plating current corresponding to a first saturation magnetization;
changing the first plating current to a second plating current;
plating a second layer of the first portion at the second plating current; and
optionally repeating the plating and changing steps such that the at least one of the leading shield, the trailing shield and the return pole includes a plurality of layers having a plurality of saturation magnetizations.
17. The method of claim 15 wherein the step of providing the at least one of the leading shield, the trailing shield and the return pole further includes:
providing an other of the at least the leading shield, the trailing shield and the return pole such that the other of the at least the leading shield, the trailing shield and the return pole has an additional gradient in an additional saturation magnetization such that the additional saturation magnetization decreases in the down track direction.
18. The method of claim 14 wherein the gradient in the saturation magnetization is selected from a linear gradient, a piecewise linear gradient, stepped and a smooth curve gradient.
19. The method of claim 14 wherein the side shield has a side shield saturation magnetization and the gradient is configured such that the at least one of the leading shield, the trailing shield and the return pole has the side shield saturation magnetization at a surface closest to the side shield.
20. The method of claim 14 wherein the side shield and the leading shield share a first interface, the side shield and the trailing shield share a second interface and the trailing shield and the return pole share a third interface, and wherein at least one of the side shield and the leading shield have first matching saturation magnetizations at the first interface, the side shield and the trailing shield have second matching saturation magnetizations at the second interface and the trailing shield and the return pole have third matching saturation magnetizations at the third interface.