Writer with HMTS (high moment trailing shield) aligned with spin layer
A PMR (perpendicular magnetic recording) write head configured for microwave assisted magnetic recording (MAMR) includes a spin-torque oscillator (STO) and trailing shield formed of high moment magnetic material (HMTS). By patterning the STO and the HMTS in a simultaneous process the HMTS and the STO layer are precisely aligned and have very similar cross-track widths. In addition, the write gap at an off-center location has a thickness that is independent from its center-track thickness and the write gap total width can have a flexible range whose minimum value is the same width as the STO width.
1. A method of fabricating a PMR magnetic writer that is configured for microwave assisted magnetic recording (MAMR), comprising:
providing a dielectric layer having a planar trailing-edge surface, an air-bearing surface (ABS) plane perpendicular to said planar trailing-edge surface and a trapezoidal trench formed symmetrically therein through said planar trailing-edge surface, projecting rearward in a direction perpendicular to said ABS plane and opening at said ABS plane; wherein said trench is wider at said planar trailing-edge surface and tapers downward to form a narrower leading edge; and
a main magnetic pole (MP) emerging through said trench, said MP having a trapezoidal planar ABS face symmetrically positioned within said trench at said air-bearing surface (ABS) plane, wherein said MP face is separated from walls of said trench by symmetrically placed side gaps (SG) and a leading-edge gap (LG); and
a uniformly thick spin torque oscillator (STO) layer formed contiguous with said planar trailing-edge surface of said dielectric layer, wherein said STO layer covers said planar upper surface, covers openings of said SGs and covers a trailing-edge surface of said MP; then
forming a uniformly thick, high moment trailing shield (HMTS) layer contiguously over said STO layer; then
trimming said HMTS and said STO layers in a single trimming process so that said two layers are aligned with each other and have equal widths that are equal to the trailing edge width of said MP; then
forming a write gap (WG) layer extending symmetrically from each side of said trimmed HMTS and STO layers, said WG layer thereby covering at least a portion of said planar trailing-edge surface of said dielectric layer and completely covering said SGs where they emerge at said dielectric layer at each side of said trench opening; then
laterally trimming said WG layer to a final width;
forming a trailing shield around the fabrication of material whose B s is less than that of said HMTS.
2. The method of claim 1 wherein said HMTS is a layer of magnetic material having a B s value between approximately 1 kG and 18 kG.
3. The method of claim 1 wherein said HMTS layer has a cross-track width between approximately 4 μm and 30 μm.
4. The method of claim 1 wherein said HMTS layer has a down-track thickness between approximately 100 nm and 2 μm.
5. The method of claim 1 wherein said STO layer is a multi-layered device having a cross-track width and down-track thickness that are each substantially equal to that of said HMTS layer.
6. The method of claim 1 wherein said WG layer is a layer of non-magnetic material and wherein the minimum total width of said WG layer is the width of said STO layer and the maximum width can vary between approximately 10 nm and 1 μm.
7. The method of claim 1 wherein off-center WG layer thickness ranges between approximately 2 nm and 50 nm.