# US 10,311,907 B2 · Apparatus comprising magnetically soft underlayer

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- Number: US 10,311,907 B2
- Document ID: US10311907B2
- Status: Granted
- Kind: B2
- Application number: 14/229,750
- Filed: 2014-03-28
- Published: 2014-10-23
- Granted: 2019-06-04
- Earliest claimed: 2006-06-08
- Assignees: Seagate Technology LLC
- Applicants: Seagate Technology LLC
- Inventors: Thomas P. Nolan; Li Tang; Yong-Chang Feng; Zhong (Stella) Wu; Samuel D. Harkness; Hans J. Richter; Youfeng Zheng
- Web page: https://patentgrep.com/patent/US10311907B2

## CPC

- G11B 5/667: including a soft magnetic layer
- G11B 5/1278: {specially adapted for magnetisations perpendicular to the surface of the record carrier}
- 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)

## Abstract

Provided herein is an apparatus, including a magnetically soft underlayer (SUL); an interlayer stack overlying the SUL, wherein the interlayer stack comprises a seed layer of an fcc material; and a perpendicular magnetic recording layer overlying the interlayer stack, wherein a thickness of the SUL in combination with a distance of the SUL from the perpendicular recording layer is sufficient to orient a total magnetic field corresponding to a magnetic transducer head at an angle of about 45°.

## Claims

### Claim 1

An apparatus, comprising:
a magnetically soft underlayer (SUL),
wherein the SUL has a thickness from about 1 nm to 40 nm;
an interlayer stack overlying the SUL,
wherein the interlayer stack comprises a seed layer of an fcc material; and
a perpendicular magnetic recording layer overlying the interlayer stack,
wherein the thickness of the SUL in combination with a distance of the SUL from the perpendicular recording layer is sufficient to increase a perpendicular component of a magnetic field corresponding to a magnetic transducer head at an angle approaching 45°.

### Claim 2 (depends on 1)

The apparatus of claim 1, wherein the interlayer stack has a thickness from about 5 nm to about 200 nm, and wherein the thickness of the interlayer stack corresponds to the distance of the SUL from the perpendicular recording layer.

### Claim 3 (depends on 2)

The apparatus of claim 2, wherein the interlayer stack further comprises
a spacer layer of CrTa, TaW, TiCr, or TiW underlying the seed layer,
wherein the spacer layer has a thickness from about 20 nm to about 100 nm; and
an interlayer of an hcp material overlying the seed layer,
wherein the interlayer stack prevents magnetic interaction between the SUL and the perpendicular magnetic recording layer.

### Claim 4 (depends on 2)

The apparatus of claim 2, wherein the SUL is of one or more materials selected from the group consisting of Ni; Co; Fe; a Co-containing alloy comprising CoZr, CoZrCr, or CoZrNb; an Fe-containing alloy comprising NiFe (Permalloy), FeN, FeSiAl, or FeSiAlN; and a CoFe-containing alloy comprising CoFeZrNb, CoFe, FeCoB, or FeCoC, and wherein the SUL comprises a saturation magnetization-thickness (Mst) product less than about 4 memu/cm2.

### Claim 5 (depends on 2)

The apparatus of claim 2, wherein the apparatus further comprises a ring-type magnetic transducer head in spaced adjacency to the perpendicular recording layer.

### Claim 6

An apparatus, comprising:
a magnetically soft underlayer (SUL);
an interlayer stack overlying the SUL,
wherein the interlayer stack has a thickness from 56 nm to about 200 nm, and
wherein the interlayer stack comprises a seed layer of an fcc material; and
a perpendicular magnetic recording layer overlying the interlayer stack,
wherein a thickness of the SUL in combination with a distance of the SUL from the perpendicular recording layer corresponding to the thickness of the interlayer stack is sufficient to increase a perpendicular component of a magnetic field corresponding to a magnetic transducer head at an angle approaching 45°.

### Claim 7 (depends on 6)

The apparatus of claim 6, wherein the thickness of the SUL is from about 1 nm to about 40 nm, and wherein the SUL comprises a saturation magnetization-thickness (Mst) product less than about 4 memu/cm2.

### Claim 8 (depends on 7)

The apparatus of claim 7, wherein the interlayer stack further comprises
a spacer layer of CrTa, TaW, TiCr, or TiW underlying the seed layer,
wherein the spacer layer has a thickness from about 20 nm to about 100 nm.

### Claim 9 (depends on 7)

The apparatus of claim 7, wherein the interlayer stack further comprises
an interlayer of an hcp material overlying the seed layer,
wherein the interlayer stack prevents magnetic interaction between the SUL and the perpendicular magnetic recording layer.

### Claim 10 (depends on 7)

The apparatus of claim 7, wherein the apparatus further comprises a ring-type magnetic transducer head in spaced adjacency to the perpendicular recording layer.

### Claim 11

An apparatus, comprising:
a magnetically soft underlayer (SUL);
an interlayer stack overlying the SUL,
wherein the interlayer stack comprises a seed layer of an fcc material;
a perpendicular magnetic recording layer overlying the interlayer stack; and
a means for increasing a perpendicular component of a magnetic field corresponding to a magnetic transducer head at an angle approaching 45°.

### Claim 12 (depends on 11)

The apparatus of claim 11, wherein the SUL has a thickness from about 1 nm to about 40 nm.

### Claim 13 (depends on 11)

The apparatus of claim 11, wherein the SUL comprises a saturation magnetization (Ms) from about 500 emu/cc to about 2,000 emu/cc.

### Claim 14 (depends on 12)

The apparatus of claim 12, wherein the SUL comprises a saturation magnetization-thickness (Mst) product less than about 4 memu/cm2.

### Claim 15 (depends on 14)

The apparatus of claim 14, wherein the interlayer stack has a thickness from about 5 nm to about 200 nm.

### Claim 16 (depends on 14)

The apparatus of claim 14, wherein the interlayer stack has a thickness from about 5 nm to about 30 nm.

### Claim 17 (depends on 15)

The apparatus of claim 15, wherein the interlayer stack further comprises a spacer layer underlying the seed layer, and wherein the spacer layer has a thickness from about 20 nm to about 100 nm.

### Claim 18 (depends on 17)

The apparatus of claim 17, wherein the spacer layer is of CrTa, TaW, TiCr, or TiW.

### Claim 19 (depends on 17)

The apparatus of claim 17, wherein the interlayer stack further comprises an interlayer overlying the seed layer, and wherein the interlayer is of an hcp material.

### Claim 20 (depends on 18)

The apparatus of claim 18, further comprising a magnetic transducer head, wherein the magnetic transducer head comprises a ring-type magnetic transducer head in spaced adjacency to the perpendicular recording layer, and wherein the means for orienting a total magnetic field corresponding to a magnetic transducer head at an angle of about 45° comprises a thickness of the SUL in combination with a distance of the SUL from the perpendicular recording layer sufficient to orient the total magnetic field corresponding to the ring-type magnetic transducer head at an angle of about 45°.