# US 8,568,909 B2 · Electrodeposition of FeCoNiV films with high resistivity and high saturation magnetization

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- Number: US 8,568,909 B2
- Document ID: US8568909B2
- Status: Granted
- Kind: B2
- Application number: 13/469,856
- Filed: 2012-05-11
- Published: 2012-09-06
- Granted: 2013-10-29
- Earliest claimed: 2004-06-03
- Assignees: Headway Technologies, Inc.
- Applicants: Feiyue Li; Xiaomin Liu
- Inventors: Feiyue Li; Xiaomin Liu
- Web page: https://patentgrep.com/patent/US8568909B2

## CPC

- G11B 5/1877: {including at least one magnetic thin film}
- C22C 38/10: containing cobalt
- C22C 38/12: containing tungsten, tantalum, molybdenum, vanadium, or niobium
- C25D 3/562: {containing more than 50% by weight of iron or nickel or cobalt}
- G11B 5/187: Structure or manufacture of the surface of the head in physical contact with, or immediately adjacent to the recording medium; Pole pieces; Gap features (G11B5/265, {G11B5/29} , G11B5/31 take precedence)
- G11B 5/31: using thin films {(G11B5/1274, G11B5/1278, G11B5/1874, G11B5/1875, G11B5/33, G11B5/49 take precedence; magnetic thin film structures H01F10/00)}
- G11B 5/3116: {Shaping of layers, poles or gaps for improving the form of the electrical signal transduced, e.g. for shielding, contour effect, equalizing, side flux fringing, cross talk reduction between heads or between heads and information tracks (G11B5/3113, G11B5/245 take precedence)}
- G11B 5/3133: {including layers not usually being a part of the electromagnetic transducer structure and providing additional features, e.g. for improving heat radiation, reduction of power dissipation, adaptations for measurement or indication of gap depth or other properties of the structure (G11B5/3106 takes precedence)}
- Y10T 428/11: Magnetic recording head
- Y10T 428/1121: Multilayer
- Y10T 428/115: Magnetic layer composition
- Y10T 428/1193: with interlaminar component [e.g., adhesion layer, etc.]
- 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)
- C22C: ALLOYS (treatment of alloys C21D, C22F)
- C25D: PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

A magnetic layer that may serve as a top pole layer and bottom pole layer in a magnetic write head is disclosed. The magnetic layer has a composition represented by FeWCoXNiYVZ in which w, x, y, and z are the atomic % of Fe, Co, Ni, and V, respectively, and where w is between about 60 and 85, x is between about 10 and 30, y is between 0 and about 20, z is between about 0.1 and 3, and wherein w+x+y+z=100. An electroplating process having a plating current density of 3 to 30 mA/cm2 is used to deposit the magnetic layer and involves an electrolyte solution with a small amount of VOSO4 which is the V source. The resulting magnetic layer has a magnetic saturation flux density BS greater than 1.9 Telsa and a resistivity ρ higher than 70 μohms-cm.

## Claims

### Claim 1

A magnetic layer having an elemental composition, comprising:
(a) about 60 to less than 80 atomic % iron;
(b) about 10 to 30 atomic % cobalt;
(c) 0 to about 20 atomic % nickel; and
(d) about 0.1 to 3 atomic % vanadium wherein a total atomic % for the FeCoV or FeCoNiV layer is 100 atomic %.

### Claim 2 (depends on 1)

The magnetic layer of claim 1 wherein the FeCoV or FeCoNiV layer is formed as a top pole layer in a magnetic write head.

### Claim 3 (depends on 2)

The magnetic layer of claim 2 wherein said top pole layer has a thickness of about 0.3 to 4 microns.

### Claim 4 (depends on 1)

The magnetic layer of claim 1 wherein the FeCoV or FeCoNiV layer is formed as a top pole layer and as a bottom pole layer in a magnetic write head.

### Claim 5 (depends on 1)

The magnetic layer of claim 1 wherein the magnetic saturation flux density BS is greater than 1.9 Telsa and the resistivity ρ is higher than 70 μohms-cm.

### Claim 6 (depends on 1)

The magnetic layer of claim 1 wherein the FeCoNiV layer has a composition of about 70 to 80 atomic % Fe, about 10 to 20 atomic % Co, about 3 to 5 atomic % Ni, and about 0.1 to 2% V and wherein the BS is greater than 1.9 T, ρ is larger than 70 μohms-cm, the easy axis coercive field (HC) is less than 20 Oe, and the anisotropy field (HK) is less than 30 Oe.

### Claim 7 (depends on 1)

The magnetic layer of claim 1 wherein the FeCoV or FeCoNiV layer is formed on a seed layer that is one of CoFe, CoFeN, or NiFe, or the seed layer has the same elemental composition as the magnetic layer.

### Claim 8

A magnetic write head, comprising:
(a) a bottom pole layer formed on a substrate;
(b) a write gap layer on said bottom pole layer;
(c) a seed layer that contacts a top surface of the write gap layer, the seed layer is made of CoFe, NiFe, CoFeN, or has a composition represented by FeWCoXNiYVZ in which w, x, y, and z are the atomic % of Fe, Co, Ni, and V, respectively, and where w is between about 60 and 85, x is between about 10 and 30, y is between 0 and about 20, z is between about 0.1 and 3, and wherein w+x+y+z=100; and
(d) a top pole layer contacting a top surface of the seed layer wherein said top pole layer and the bottom pole layer have an equivalent FeWCoXNiYVZ composition.

### Claim 9 (depends on 8)

The magnetic write head of claim 8 wherein the magnetic write head is part of a separated read-write head structure and the bottom pole layer is formed on an Al2O3 layer that separates the write head from the read head.

### Claim 10 (depends on 8)

The magnetic write head of claim 8 wherein the magnetic write head is a planar writer, a stitched pole writer, or a perpendicular recording head.

### Claim 11 (depends on 8)

The magnetic write head of claim 8 wherein the bottom pole layer has a thickness of about 3 to 6 microns.

### Claim 12 (depends on 8)

The magnetic write head of claim 8 wherein the seed layer has a thickness of about 0.05 to 0.4 microns.

### Claim 13 (depends on 8)

The magnetic write head of claim 8 wherein the top pole layer has a thickness of about 0.3 to 4 microns and a track width of about 0.2 to 0.4 microns.

### Claim 14 (depends on 8)

The magnetic write head of claim 8 wherein the top pole layer has a magnetic saturation flux density BS greater than 1.9 Telsa and a resistivity ρ higher than 70 μohms-cm.

### Claim 15 (depends on 8)

The magnetic write head of claim 8 wherein the top pole layer has a composition of about 70 to 80 atomic % Fe, about 10 to 20 atomic % Co, about 3 to 5 atomic % Ni, and about 0.1 to 2% V and wherein the BS is greater than 1.9 T, ρ is larger than 70 μohms-cm, the easy axis coercive field (HC) is less than 20 Oe, and the anisotropy field (HK) is less than 30 Oe.