# US 10,121,499 B2 · Magnetoresistive sensor with enhanced uniaxial anisotropy

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- Number: US 10,121,499 B2
- Document ID: US10121499B2
- Status: Granted
- Kind: B2
- Application number: 15/618,970
- Filed: 2017-06-09
- Published: 2017-09-28
- Granted: 2018-11-06
- Earliest claimed: 2015-09-11
- Assignees: Seagate Technology LLC
- Applicants: Seagate Technology LLC
- Inventors: Sameh Hassan; Wonjoon Jung; Mark Kief; Marcus Ormston
- Web page: https://patentgrep.com/patent/US10121499B2

## CPC

- G11B 5/3163: {Fabrication methods or processes specially adapted for a particular head structure, e.g. using base layers for electroplating, using functional layers for masking, using energy or particle beams for shaping the structure or modifying the properties of the basic layers}
- G01R 33/09: Magnetoresistive devices
- 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 5/313: {Disposition of layers}
- G11B 5/3906: {Details related to the use of magnetic thin film layers or to their effects}
- 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)}
- G11B 5/398: {Specially shaped layers}
- H10N 50/20: Spin-polarised current-controlled devices (magnetoresistive devices H10N50/10)
- 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)
- G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12)
- H10N: ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR

## Abstract

A read sensor that includes a free layer having a magnetization that changes according to an external magnetic field. The read sensor also includes an additional magnetic layer and a non-magnetic layer. The non-magnetic layer may include a corrugated surface facing the additional magnetic layer. The corrugated surface is configured to enhance uniaxial anisotropy in the read sensor.

## Claims

### Claim 1

A method of forming a reader, the method comprising:
forming a non-magnetic layer having a corrugated or rough upper surface;
forming a first pinned layer on the corrugated or rough upper surface of the non-magnetic layer, wherein the first pinned layer comprises a bottom surface and a top surface, and wherein the bottom surface of the first pinned layer is in contact with the corrugated or rough upper surface, and wherein at least a portion of the top surface of the first pinned layer above the corrugated or rough upper surface is uneven;
performing a smoothing operation on the top surface of the first pinned layer to remove the unevenness by:
depositing a cap layer on the top surface of the first pinned layer; and
applying plasma treatment to the cap layer and the first pinned layer to remove the cap layer and to partially remove the first pinned layer to provide a smooth top surface of the first pinned layer; and
forming a free layer over the first pinned layer.

### Claim 2 (depends on 1)

The method of claim 1 and further comprising forming an antiferromagnetic (AFM) layer adjacent, to the first pinned layer.

### Claim 3 (depends on 1)

The method of claim 1 and further comprising forming a second pinned layer on the smooth top surface of the first pinned layer.

### Claim 4 (depends on 3)

The method of claim 3 and further comprising forming a separation layer on the second pinned layer.

### Claim 5 (depends on 4)

The method of claim 4 and further comprising forting the free layer on the separation layer.

### Claim 6

A method of forming a reader comprising:
forming a bottom shield having a bottom surface, a top surface, a front surface and a back surface, wherein the front surface of the bottom shield forms a portion of a bearing surface of the reader;
forming a recessed antiferromagnetic (AFM) layer on a rear portion of the top surface of the bottom shield, wherein the recessed AFM layer comprises a bottom surface, a top surface, a front surface and a back surface;
forming a reader front shield on a front portion of the top surface of the bottom shield, wherein the reader front shield comprises a bottom surface, a top surface, a front surface and a back surface, wherein the back surface of the reader front shield is in contact with the front surface of the recessed AFM layer, and wherein the front surface of the reader front shield forms a portion of the bearing surface;
forming a non-magnetic layer on the top surface of the reader front shield, wherein the non-magnetic layer comprises a bottom surface, a top surface, a front surface and a back surface, wherein the top surface of the non-magnetic layer is a corrugated surface, and wherein the front surface of the non-magnetic layer forms a portion of the bearing surface; and
forming a pinned magnetic layer over the top surface of the recessed AFM layer and over the corrugated surface of the non-magnetic layer;
forming a free layer over the pinned magnetic layer.

### Claim 7 (depends on 6)

The method of claim 6 and wherein forming the pinned magnetic layer comprises forming a first pinned layer on the top surface of the recessed AFM layer and on the corrugated surface of the non-magnetic layer, and wherein the first pinned layer comprises a bottom surface, a top surface, a back surface and a front surface, and wherein a front surface of the first pinned layer forms a portion of the bearing surface, and wherein at least a portion of the top surface of the first pinned layer above the corrugated surface in uneven.

### Claim 8 (depends on 7)

The method of claim 7 and further comprising performing a smoothing operation on the top surface of the first pinned layer to remove the unevenness.

### Claim 9 (depends on 8)

The method of claim 8 and wherein performing the smoothing operation to remove the unevenness comprises:
depositing a cap layer on the top surface of the first pinned layer; and
applying plasma treatment to the cap layer and the first pinned layer to remove the cap layer and to partially remove the first pinned layer to provide a smooth top surface of the pinned layer.

### Claim 10 (depends on 9)

The method of claim 9 and wherein forming the pinned magnetic layer further comprises forming a second pinned layer on the smooth top surface of the first pinned layer.

### Claim 11 (depends on 10)

The method of claim 10 and further comprising forming a separation layer on the second pinned layer.

### Claim 12 (depends on 11)

The method of claim 11 and further comprising forming the free layer on the separation layer.

### Claim 13

A method of forming a reader, the method comprising:
forming a bottom shield;
forming a non-magnetic layer over the bottom shield, the non-magnetic layer having a corrugated or rough upper surface;
forming a first pinned layer on the corrugated or rough upper surface of the non-magnetic layer, wherein the first pinned layer comprises a bottom surface and a top surface, and wherein the bottom surface of the first pinned layer is in contact with the corrugated or rough upper surface, and wherein at least a portion of the top surface of the first pinned layer above the corrugated or rough upper surface is uneven;
performing a smoothing operation on the top surface of the first pinned layer to remove the unevenness by:
depositing a cap layer on the top surface of the first pinned layer; and
applying plasma treatment to the cap layer and the first pinned layer to remove the cap layer and to partially remove the first pinned layer to provide a smooth top surface of the first pinned layer; and
forming a free layer over the first pinned layer.

### Claim 14 (depends on 13)

The method of claim 13 and further comprising forming an antiferromagnetic (AFM) layer adjacent to the first pinned layer.

### Claim 15 (depends on 13)

The method of claim 13 and further comprising forming a second pinned layer on the smooth top surface of the first pinned layer.

### Claim 16 (depends on 15)

The method of claim 15 and further comprising forming a separation layer on the second pinned layer.

### Claim 17 (depends on 16)

The method of claim 16 and further comprising forming the free layer on the separation layer.