THIN MAGNETIC FILM, METHOD OF MANUFACTURING THE SAME, AND HIGH FREQUENCY OSCILLATOR, MAGNETIC HEAD, MAGNETIC RECORDING MEDIUM, AND MAGNETIC RECORDING/REPRODUCING APPARATUS USING THIN MAGNETIC FILM

• US 20140139952A1
• Filed: 07/19/2013
• Published: 05/22/2014
• Est. Priority Date: 11/16/2012
• Status: Active Grant

• Current Assignee: Resonac Corp. (Resonac Holdings Corp.), Tohoku University National Universities Corporation, Toshiba Electronic Devices & Storage Corporation (Toshiba Corporation)
• Original Assignee: Showa Denko KK (Resonac Holdings Corp.), Tohoku University National Universities Corporation, Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Takeo, Akihiko, Kikitsu, Akira, Maeda, Tomoyuki, Takahashi, Migaku, Saito, Shin, Kurokawa, Gohei, Inoue, Ken
• Granted Patent: US 8,837,087 B2
• Time in Patent Office: Days
• US Class Current: 360/125.03
• CPC Class Codes: G11B 2005/0024 Microwave assisted recording
• CPC Class Codes: G11B 5/1278 specially adapted for magnetisations perpendicular to the surface of the record carrier
• CPC Class Codes: G11B 5/235 Selection of material for gap filler G11B5/232 takes precedence
• CPC Class Codes: G11B 5/3146 magnetic layers
• CPC Class Codes: G11B 5/656 containing Co containing inorganic, non-oxide compounds of Si, N, P, B, H or C G11B5/657; containing oxygen G11B5/658
• CPC Class Codes: G11B 5/736 Non-magnetic layer under a soft magnetic layer, e.g. between a substrate and a soft magnetic underlayer [SUL] or a keeper layer magnetic recording media substrates G11B5/739
• CPC Class Codes: G11B 5/7368 Non-polymeric layer under the lowermost magnetic recording layer base layers having a non-magnetic layer under a soft magnetic layer G11B5/736; magnetic recording media substrates G11B5/739
• CPC Class Codes: G11B 5/7369 Two or more non-magnetic underlayers, e.g. seed layers or barrier layers
• CPC Class Codes: G11B 5/7379 Seed layer, e.g. at least one non-magnetic layer is specifically adapted as a seed or seeding layer
• CPC Class Codes: 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
• CPC Class Codes: H01F 10/3286 Spin-exchange coupled multilayers having at least one layer with perpendicular magnetic anisotropy
• CPC Class Codes: H01F 10/329 Spin-exchange coupled multilayers wherein the magnetisation of the free layer is switched by a spin-polarised current, e.g. spin torque effect
• CPC Class Codes: H01F 41/30 for applying nanostructures, e.g. by molecular beam epitaxy [MBE]
• CPC Class Codes: H03B 15/006 using spin transfer effects or giant magnetoresistance
• CPC Class Codes: H03B 28/00 Generation of oscillations by methods not covered by groups H03B5/00 - H03B27/00, including modification of the waveform to produce sinusoidal oscillations analogue function generators for performing computing operations G06G7/26; use of transformers for conversion of waveform in ac-ac converters H02M5/18

Abstract

According to one embodiment, there is provided a thin magnetic film having a negative anisotropy of −6×10⁶ erg/cm³ or less and including, on at least a nonmagnetic substrate, at least one seed layer made of a metal or metal compound, a ruthenium underlayer for controlling the orientation of an immediately overlying layer, and a magnetic layer having negative anisotropy in the normal line direction perpendicular to a surface of the magnetic layer and mainly containing Co and Ir, wherein the additive element concentration of Ir in the magnetic layer is 10 (inclusive) to 45 (inclusive) at %.

Claims

1. A thin magnetic film comprising:

a nonmagnetic substrate;

a ruthenium underlayer formed on the nonmagnetic substrate; and

a magnetic layer formed in contact with the ruthenium underlayer, having a negative anisotropy of −

6×

10⁶ to −

1.2×

10⁷ erg/cm³ (−

6×

10⁸ to −

1.2×

10⁹ nJ/cm³) in a normal line direction perpendicular to a surface of the magnetic layer, and mainly containing Co_1-xIr_x (x=10 to 45 at %).

2. The film according to claim 1, wherein the ruthenium underlayer is annealed at a temperature of 400°

C. (inclusive) to 650°

C. (exclusive).

3. The film according to claim 1, further comprising, between the nonmagnetic substrate and the ruthenium underlayer, a seed layer made of at least one material selected from the group consisting of tantalum, platinum, titanium, and nickel.

4. A thin magnetic film manufacturing method comprising:

forming a ruthenium underlayer on a nonmagnetic substrate;

annealing the ruthenium underlayer at a temperature of 400°

C. (inclusive) to 650°

C. (exclusive); and

forming a magnetic layer mainly containing Co_1-xIr_x (x=10 to 45 at %), in contact with the annealed ruthenium underlayer.

5. The method according to claim 4, further comprising, before the forming the ruthenium underlayer on the nonmagnetic substrate, forming a seed layer made of at least one material selected from the group consisting of tantalum, platinum, titanium, and nickel.

6. A high frequency oscillator comprising:

a first electrode;

a ruthenium underlayer formed on the first electrode;

a first magnetic layer formed in contact with the ruthenium underlayer, having a negative anisotropy of −

6×

10⁶ to −

1.2×

10⁷ erg/cm³ (−

6×

10⁸ to −

1.2×

10⁹ nJ/cm³) in a normal line direction perpendicular to a surface of the first magnetic layer, and mainly containing Co_1-xIr_x (x=10 to 45 at %);

a nonmagnetic interlayer formed on the first magnetic layer;

a second magnetic layer formed on the nonmagnetic interlayer, having perpendicular magnetic anisotropy, and containing at least one magnetic material selected from the group consisting of iron, cobalt, and nickel; and

a second electrode formed on the second magnetic layer.

7. The oscillator according to claim 6, wherein the ruthenium underlayer is annealed at a temperature of 400°

C. (inclusive) to 650°

C. (exclusive).

8. The oscillator according to claim 6, further comprising, between the nonmagnetic substrate and the ruthenium underlayer, a seed layer made of at least one material selected from the group consisting of tantalum, platinum, titanium, and nickel.

9. A magnetic head comprising:

a main magnetic pole;

a recording magnetic pole forming a magnetic circuit together with the main magnetic pole; and

a high frequency oscillator formed between the main magnetic pole and the recording magnetic pole and comprising

a first electrode,

a ruthenium underlayer formed on the first electrode,

a first magnetic layer formed in contact with the ruthenium underlayer, having a negative anisotropy of −

6×

10⁶ to −

1.2×

10⁷ erg/cm³ (−

6×

10⁸ to −

1.2×

10⁹ nJ/cm³) in a normal line direction perpendicular to a surface of the first magnetic layer, and mainly containing Co_1-xIr_x (x=10 to 45 at %),

a nonmagnetic interlayer formed on the first magnetic layer,

a second magnetic layer formed on the nonmagnetic interlayer, having perpendicular magnetic anisotropy, and containing at least one magnetic material selected from the group consisting of iron, cobalt, and nickel, and

a second electrode formed on the second magnetic layer.

10. A magnetic recording/reproducing apparatus including a magnetic head comprising:

a main magnetic pole;

a recording magnetic pole forming a magnetic circuit together with the main magnetic pole; and

a high frequency oscillator formed between the main magnetic pole and the recording magnetic pole and comprising

a first electrode,

a ruthenium underlayer formed on the first electrode,

a first magnetic layer formed in contact with the ruthenium underlayer, having a negative anisotropy of −

6×

10⁶ to −

1.2×

10⁷ erg/cm³ (−

6×

10⁸ to −

1.2×

10⁹ nJ/cm³) in a normal line direction perpendicular to a surface of the first magnetic layer, and mainly containing Co_1-xIr_x (x=10 to 45 at %),

a nonmagnetic interlayer formed on the first magnetic layer,

a second magnetic layer formed on the nonmagnetic interlayer, having perpendicular magnetic anisotropy, and containing at least one type of a magnetic material selected from the group consisting of iron, cobalt, and nickel, and

a second electrode formed on the second magnetic layer.

11. A perpendicular magnetic recording medium comprising:

a nonmagnetic substrate;

a ruthenium underlayer formed on the nonmagnetic substrate;

a soft magnetic backing layer formed in contact with the ruthenium underlayer, having a negative anisotropy of −

6×

10⁶ to −

1.2×

10⁷ erg/cm³ (−

6×

10⁸ to −

1.2×

10⁹ nJ/cm³) in a normal line direction perpendicular to a surface of the soft magnetic backing layer and mainly containing Co_1-xIr_x (x=10 to 45 at %); and

a perpendicular magnetic recording layer formed on the soft magnetic backing layer and containing cobalt, chromium, and platinum.

12. The medium according to claim 11, wherein the ruthenium underlayer is annealed at a temperature of 400°

C. (inclusive) to 650°

C. (exclusive).

13. The medium according to claim 11, further comprising, between the nonmagnetic substrate and the ruthenium underlayer, a seed layer made of at least one type of a material selected from the group consisting of tantalum, platinum, titanium, and nickel.

14. A magnetic recording/reproducing apparatus comprising:

a perpendicular magnetic recording medium comprising

a nonmagnetic substrate,

a ruthenium underlayer formed on the nonmagnetic substrate,

a soft magnetic backing layer formed in contact with the ruthenium underlayer, having a negative anisotropy of −

6×

10⁶ to −

1.2×

10⁷ erg/cm³ (−

6×

10⁸ to −

1.2×

10⁹ nJ/cm³) in a normal line direction perpendicular to a surface of the soft magnetic backing layer, and mainly containing Co_1-xIr_x (x=10 to 45 at %), and

a perpendicular magnetic recording layer formed on the soft magnetic backing layer and containing cobalt, chromium, and platinum; and

a magnetic head.