# US 8,570,691 B2 · TMR sensor film using a tantalum insertion layer and systems thereof

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- Number: US 8,570,691 B2
- Document ID: US8570691B2
- Status: Granted
- Kind: B2
- Application number: 13/082,098
- Filed: 2011-04-07
- Published: 2012-10-11
- Granted: 2013-10-29
- Earliest claimed: 2011-04-07
- Assignees: HGST Netherlands B.V.
- Applicants: Masashige Sato; Kojiro Komagaki
- Inventors: Masashige Sato; Kojiro Komagaki
- Web page: https://patentgrep.com/patent/US8570691B2

## CPC

- G11B 5/3909: {Arrangements using a magnetic tunnel junction}
- Y10T 428/1114: having tunnel junction effect
- 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)
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

In one embodiment, a tunnel magnetoresistance (TMR) head includes a lead layer above a substrate, a seed layer above the lead layer, an antiferromagnetic (AFM) layer above the seed layer, a first ferromagnetic layer above the AFM layer, a second ferromagnetic layer above the first ferromagnetic layer, a coupling layer between the first and second ferromagnetic layers, the coupling layer causing a magnetization of the second ferromagnetic layer to be coupled to a magnetization of the first ferromagnetic layer, a fixed layer above the second ferromagnetic layer, an insertion layer adjacent the fixed layer or in the fixed layer, a barrier layer above the fixed layer, a free layer above the barrier layer, and a cap layer above the free layer. In another embodiment, the insertion layer is from about 0.05 nm to 0.3 nm in thickness and includes Ta, Ti, Hf, and/or Zr, and the free layer includes CoFeB.

## Claims

### Claim 1

A tunnel magnetoresistance (TMR) head, comprising:
a lead layer above a substrate;
a seed layer above the lead layer;
an antiferromagnetic (AFM) layer above the seed layer;
a first ferromagnetic layer above the AFM layer;
a second ferromagnetic layer above the first ferromagnetic layer;
a coupling layer between the first and second ferromagnetic layers, the coupling layer causing a magnetization of the second ferromagnetic layer to be coupled to a magnetization of the first ferromagnetic layer;
a fixed layer above the second ferromagnetic layer;
an insertion layer in the fixed layer;
a barrier layer above the fixed layer;
a free layer above the barrier layer;
a cap layer above the free layer; and
a third ferromagnetic layer above the fixed layer and below the barrier layer, wherein the insertion layer is positioned in the fixed layer closer to an interface of the fixed layer and the second ferromagnetic layer than an interface of the fixed layer and the third ferromagnetic layer.

### Claim 2 (depends on 1)

The TMR head as recited in claim 1, wherein the lead layer comprises a stack of alternating layers of Cu and Ta above a NiFe underlayer.

### Claim 3 (depends on 1)

The TMR head as recited in claim 1, wherein the AFM layer comprises at least one of: MnIr and MnPt.

### Claim 4 (depends on 1)

The TMR head as recited in claim 1, wherein the first and second ferromagnetic layers comprise at least one of: NiFe and CoFe.

### Claim 5 (depends on 1)

The TMR head as recited in claim 1, wherein the second ferromagnetic layer is crystalline and has a thickness in a range from about 0.2 nm to about 1.0 nm.

### Claim 6 (depends on 1)

The TMR head as recited in claim 1, further comprising a third ferromagnetic layer above the fixed layer and below the barrier layer, wherein the third ferromagnetic layer comprises at least one of: NiFe and CoFe.

### Claim 7 (depends on 1)

The TMR head as recited in claim 1, wherein the coupling layer has a thickness in a range from about 0.4 nm to about 1.5 nm and comprises at least one of: Ru, Ir, Rh, Cr, Cu, and Hf.

### Claim 8 (depends on 1)

The TMR head as recited in claim 1, wherein the fixed layer comprises an amorphous ferromagnetic material and has a thickness in a range from about 0.5 nm to about 2.0 nm.

### Claim 9 (depends on 8)

The TMR head as recited in claim 8, wherein the fixed layer has an amorphous structure, and comprises at least one of: CoFeB and CoFeHf.

### Claim 10 (depends on 1)

The TMR head as recited in claim 1, wherein the insertion layer has a thickness in a range from about 0.05 nm to about 0.3 nm and comprises at least one of: Ta, Ti, Hf, and Zr.

### Claim 11 (depends on 10)

The TMR head as recited in claim 10, wherein the insertion layer comprises Ta.

### Claim 12 (depends on 1)

The TMR head as recited in claim 1, wherein the free layer has a thickness in a range from about 4.0 nm to about 8.0 nm and comprises a ferromagnetic material selected from a group consisting of: CoFe, CoFeB, and CoFeHf.

### Claim 13 (depends on 1)

A magnetic data storage system, comprising:
a magnetic medium;
at least one TMR head as recited in claim 1 for reading from/writing to the magnetic medium;
a drive mechanism for passing the magnetic medium over the at least one TMR head; and
a controller electrically coupled to the at least one TMR head for controlling operation of the at least one TMR head.

### Claim 14

A tunnel magnetoresistance (TMR) head, comprising:
a lead layer above a substrate;
a seed layer above the lead layer;
an antiferromagnetic (AFM) layer above the seed layer;
a first ferromagnetic layer above the AFM layer;
a second ferromagnetic layer above the first ferromagnetic layer;
a coupling layer between the first and second ferromagnetic layers, the coupling layer causing a magnetization of the second ferromagnetic layer to be coupled to a magnetization of the first ferromagnetic layer;
a fixed layer above the second ferromagnetic layer;
an insertion layer in the fixed layer;
a barrier layer above the fixed layer;
a free layer above the barrier layer;
a cap layer above the free layer; and
a third ferromagnetic layer above the fixed layer and below the barrier layer, wherein the insertion layer is positioned in the fixed layer about equidistant from an interface of the fixed layer and the second ferromagnetic layer to an interface of the fixed layer and the third ferromagnetic layer.