# US 9,520,147 B2 · Side shielded magnetoresistive (MR) read head with perpendicular magnetic free layer

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 9,520,147 B2
- Document ID: US9520147B2
- Status: Granted
- Kind: B2
- Application number: 14/581,141
- Filed: 2014-12-23
- Published: 2015-04-23
- Granted: 2016-12-13
- Earliest claimed: 2010-05-05
- Assignees: Headway Technologies, Inc.
- Applicants: Headway Technologies, Inc.
- Inventors: Yuchen Zhou; Kunliang Zhang; Zhigang Bai
- Web page: https://patentgrep.com/patent/US9520147B2

## CPC

- G11B 5/398: {Specially shaped layers}
- B82Y 10/00: Nanotechnology for information processing, storage or transmission, e.g. quantum computing or single electron logic
- B82Y 25/00: Nanomagnetism, e.g. magnetoimpedance, anisotropic magnetoresistance, giant magnetoresistance or tunneling magnetoresistance
- B82Y 40/00: Manufacture or treatment of nanostructures
- G01R 33/093: {using multilayer structures, e.g. giant magnetoresistance sensors (thin magnetic films H01F10/00)}
- G01R 33/098: {comprising tunnel junctions, e.g. tunnel magnetoresistance sensors}
- G11B 5/3909: {Arrangements using a magnetic tunnel junction}
- G11B 5/3912: {Arrangements in which the active read-out elements are transducing in association with active magnetic shields, e.g. magnetically coupled shields (G11B5/3916 takes precedence)}
- H01F 10/30: characterised by the composition of the intermediate layers {, e.g. seed, buffer, template, diffusion preventing, cap layers (H01F10/06 and H01F10/32 take precedence)}
- H01F 10/3259: {Spin-exchange-coupled multilayers comprising at least a nanooxide layer [NOL], e.g. with a NOL spacer}
- H01F 10/3286: {Spin-exchange coupled multilayers having at least one layer with perpendicular magnetic anisotropy}
- H01F 10/3295: {Spin-exchange coupled multilayers wherein the magnetic pinned or free layers are laminated without anti-parallel coupling within the pinned and free layers}
- H01F 41/307: {insulating or semiconductive spacer}
- H10N 50/10: Magnetoresistive devices
- H10N 50/80: Constructional details
- G11B 5/3906: {Details related to the use of magnetic thin film layers or to their effects}
- G11B 2005/3996: {large or giant magnetoresistive effects [GMR], e.g. as generated in spin-valve [SV] devices}
- G11B: INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER (recording measured values in a way that does not require playback through a transducer G01D9/00; recording or playback apparatus using mechanically marked tape, e.g. punched paper tape, or using unit records, e.g. punched or magnetically marked cards G06K; transferring data from one type of record carrier to another G06K1/18; circuits for coupling output of reproducer to radio receiver H04B1/20; gramophone pick-ups or like acoustic electromechanical transducers or circuits therefor H04R)
- B82Y: SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
- G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12)
- H01F: MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H10N: ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR

## Abstract

A MR sensor is disclosed that has a free layer (FL) with perpendicular magnetic anisotropy (PMA) which eliminates the need for an adjacent hard bias structure to stabilize free layer magnetization and minimizes shield-FL interactions. In a TMR embodiment, a seed layer, free layer, junction layer, reference layer, and pinning layer are sequentially formed on a bottom shield. After patterning, a conformal insulation layer is formed along the sensor sidewall. Thereafter, a top shield is formed on the insulation layer and includes side shields that are separated from the FL by a narrow read gap. The sensor is scalable to widths <50 nm when PMA is greater than the FL self-demag field. Effective bias field is rather insensitive to sensor aspect ratio which makes tall stripe and narrow width sensors a viable approach for high RA TMR configurations. Sensor sidewalls may extend into the seed layer or bottom shield.

## Claims

### Claim 1

A magneto-resistive (MR) sensor, comprising:
(a) a bottom shield having a top surface;
(b) a patterned sensor stack of layers including a seed layer, magnetic free layer, junction layer, magnetic reference layer, and an exchange pinning layer that are sequentially formed on a pedestal portion of the bottom shield top surface, the pedestal portion has a side that extends below a bottom surface of the seed layer, and said free layer has a magnetization and magnetic anisotropy formed perpendicular to the top surface of the bottom shield in a zero field environment, and parallel to the bottom shield top surface when a magnetic field is applied in an in-plane direction, the reference layer has a magnetization parallel to the bottom shield top surface wherein the reference layer's magnetization direction is maintained by exchange coupling from the exchange pinning layer, and each of the layers in the sensor stack adjoins an air bearing surface (ABS);
(c) an insulation layer adjoining the side of the pedestal portion and formed on a portion of the bottom shield top surface adjacent to the pedestal portion; and
(d) a top shield contacting a top surface of the patterned sensor stack such that there is electrical contact between the top and bottom shields, said top shield includes side shield sections formed on and adjoining the insulation layer, the side shield sections have a bottom surface formed below a top surface of the pedestal portion of the bottom shield.

### Claim 2 (depends on 1)

The MR sensor of claim 1 wherein the seed layer promotes perpendicular magnetic anisotropy in the free layer.

### Claim 3 (depends on 1)

The MR sensor of claim 1 wherein the seed layer is selected from one of Ta, Ru, Ti, Cu, Ag, Au, NiCr, NiFeCr, CrTi, or a combination of one or more of the aforementioned elements and alloys including a composite that is Ta/Ti/Cu.

### Claim 4 (depends on 1)

The MR sensor of claim 1 wherein the free layer is a (Co/Ni)x multilayer or a (CoFe/Ni)x multilayer where x is from about 5 to 50.

### Claim 5 (depends on 1)

The MR sensor of claim 1 wherein the free layer is made of (Co/Pt)Y, (Fe/Pt)Y, (CoFe/Pt)Y, or (Co/Pd)Y where y is an integer, or is a single layer of FePt, CoPt, or CoCrPt.

### Claim 6 (depends on 1)

The MR sensor of claim 1 wherein the free layer is a composite with an upper FL1 soft magnetic layer contacting the junction layer, and a lower FL2 layer having perpendicular magnetic anisotropy, said FL1 layer has a magnetization perpendicular to the plane of the free layer because of exchange coupling with the FL2 layer.

### Claim 7 (depends on 6)

The MR sensor of claim 6 wherein the FL1 layer is comprised of CoFe, CoFeB, or combinations thereof.

### Claim 8 (depends on 1)

The MR sensor of claim 1 wherein the reference layer is a soft magnetic layer made of one or more of Co, Fe, Ni, B, and Ta, or is a composite comprising CoFeB and CoFe.

### Claim 9 (depends on 1)

The MR sensor of claim 1 wherein the exchange pinning layer is an anti-ferromagnetic (AFM) layer that pins the reference layer.