Optimizing a current distribution in write heads for efficient energy-assisted magnetic recording

Patent metadata

Field	Value
Publication number	US-12525255-B2
Application number	US-202418826835-A
Country	US
Kind code	B2
Filing date	Sep 6, 2024
Priority date	Aug 30, 2023
Publication date	Jan 13, 2026
Grant date	Jan 13, 2026

Abstract

The present embodiments can generally provide a magnetic write head structure with optimized gap current distribution to maximize the current-assisted areal density capacity (ADC) gain in hard-disk-drive storage devices. In a first example embodiment, a non-dual-write-shield (nDWS) write head can include a main pole (MP), a trailing shield (TS), and a write gap (WG) disposed between the MP and the TS. The write head can also include a side shield (SS), a leading shield (LS), and a write shield (WS). The write head can include a side gap (SG) between the MP and the SS on both sides of the MP tip, and a leading gap (LG) between the MP and the LS. The write head can also include a coil wrapped around the MP through a PP3 shield that is configured to direct a time-dependent write current to saturate magnetization of the MP.

First claim

What is claimed is:

1 . A non-dual-write-shield (nDWS) write head comprising:
a main pole (MP); a trailing shield (TS); a write gap (WG) disposed between the MP and the TS; a side shield (SS), a leading shield (LS), and a write shield (WS) configured to prevent a magnetic flux from reaching components disposed away from a tip of the MP; and a first insulator starting a first distance from the MP and ends at a second distance from the MP, wherein the WS is electrically isolated from the SS via the first insulator.

2 . The nDWS write head of claim 1 , further comprising:
a side gap (SG) between the MP and the SS on both sides of the MP tip; a leading gap (LG) between the MP and the LS; and a coil wrapped around the MP through a PP3 shield that is configured to direct a time-dependent write current to saturate magnetization of the MP.

3 . The nDWS write head of claim 2 , wherein a current is configured to be provided through the MP to one of a side of the WS or SS to induce a current-assisted ADC gain, wherein the current can enter through the SS, LL, and WS to the MP tip via the SG, LG, and WG, and wherein a current distribution is based on path resistances of different gaps.

4 . The nDWS write head of claim 2 , wherein the WS is electrically connected to the SS along a length of the WS and SS, wherein more current is configured to flow in the SG and LG combined than that in the WG.

5 . The nDWS write head of claim 2 , wherein as a length of the first insulator increases, a SG and LG current decreases, and a WG current increases.

6 . The nDWS write head of claim 5 , wherein a current flow between the SG and LG is equal to that of the WG when the length of the first insulator is around 5.5 μm and the WG includes any of a NiCr or NiCr/Ru alloy material.

7 . The nDWS write head of claim 2 , further comprising:
a second insulator on the SG, wherein the second insulator is configured to prevent a SG current and avoid an SG current-induced ATI degradation.

8 . The nDWS write head of claim 2 , further comprising:
a resistor disposed between the WS and a ground, wherein the resistor allows for a current distribution to be equal between the WG and the SG and the LG.

9 . The nDWS write head of claim 2 , further comprising:
a conductive layer connected to the LS, wherein a MP to SS/LS path resistance is reduced with an additional shunting path created by connecting the LS to the conductive layer.

10 . The nDWS write head of claim 2 , wherein the LS can be electrically connected to an S 2 C layer via an LSB, wherein a thickness of the S2C is ˜0.6 μm, and a height of the S2C is ˜1.5 μm.

11 . The nDWS write head of claim 10 , wherein the LSB and S2C material includes any of a 10 kG soft-magnetic material, a 19 kG soft-magnetic material, and a copper material.

12 . The nDWS write head of claim 2 , further comprising:
a low-resistive soft-magnetic layer connected to the LS.

13 . The nDWS write head of claim 12 , wherein the low-resistive soft-magnetic layer includes any of a 10 kG soft-magnetic material, a 19 kG soft-magnetic material, and a 24 kG soft-magnetic material.

14 . The nDWS write head of claim 12 , wherein the low-resistive soft-magnetic layer has a curved shape with the middle region with a length being the same height as the LS, and then the height gradually increases to 0.6 μm on both ends, and wherein each end of the low-resistive soft-magnetic layer is connected using an additional copper wire that wraps around the MP to avoid any electrical contact with other parts of the write head.

15 . The nDWS write head of claim 1 , wherein the WG includes a magnetic or a non-magnetic conducting element.

16 . The nDWS write head of claim 15 , wherein the WG element is part of a multi-layered structure including a GMR element or a 2E+n element, wherein the multi-layered structure includes a first non-magnetic spacer, an iron-nickel (NiFe) layer, a second non-magnetic spacer, a first copper-iron layer, a third non-magnetic spacer, a second copper-iron layer, and a fourth non-magnetic spacer ending at the TS.

17 . The nDWS write head of claim 1 , wherein the WG element includes a small giant-magnetoresistive (GMR) device with a thickness equal to that of the WG, wherein the WG element includes a length equal to that of a main pole tip width at the top of an air bearing surface (ABS), and the WG element including a width equal to an eTHd height of the TS.

18 . The nDWS write head of claim 1 , wherein the first distance of the first insulator is around 80 nm from the MP, wherein a thickness of the first insulator is between 3-5 nm that extends to 1.3 μm in each direction up to an edge of the WG, and wherein the thickness of the first insulator is equal to a thickness of the WG after 1.3 μm in each direction from the MP.

19 . The nDWS write head of claim 1 , further comprising:
a magnetic device connected to the WG, wherein the magnetic device has a thickness equal to that of the WG, a width of the magnetic device being equal to a eTHd height of the TS.

20 . The nDWS write head of claim 19 , wherein a third insulator under a WG is bent to extend up to the HS and create an opening of a first length to optimize a current between the WG and the magnetic device, wherein a current through the WG is constrained through the opening, wherein the first length is between 10-20 nm.

Assignees

• Headway Tech Inc

Inventors

• Sayed Shehrin
• Chen Wenyu
• Liu Yue
• Liu Kowang
• Roppongi Tetsuya
• Ren Haowen
• Tang Yuhui
• Dovek Moris Musa
• Chen Wenjie

Classifications

• G11B5/3906 Primary

  Details related to the use of magnetic thin film layers or to their effects · CPC title

• G11B2005/3996

  large or giant magnetoresistive effects [GMR], e.g. as generated in spin-valve [SV] devices · CPC title

• G11B5/315

  Shield layers on both sides of the main pole, e.g. in perpendicular magnetic heads · CPC title

• G11B5/1278

  specially adapted for magnetisations perpendicular to the surface of the record carrier · CPC title

• G11B5/23 Primary

  Gap features {(G11B5/1871, G11B5/1875, G11B5/265, G11B5/29, G11B5/488 and subgroups, G11B5/4907 and subgroups, G11B5/4969 and subgroups take precedence)} · CPC title