Perpendicular magnetic recording medium with tilted easy axis of magnetization, method of manufacturing magnetic recording medium, and magnetic recording apparatus comprising magnetic recording medium

• US 20070026262A1
• Filed: 07/26/2006
• Published: 02/01/2007
• Est. Priority Date: 07/26/2005
• Status: Active Grant

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Maeda, Tomoyuki
• Granted Patent: US 7,989,097 B2
• Time in Patent Office: Days
• US Class Current: 428/831.200
• CPC Class Codes: G11B 5/65 characterised by its composition G11B5/66 takes precedence
• CPC Class Codes: G11B 5/658 containing oxygen, e.g. molecular oxygen or magnetic oxide
• CPC Class Codes: G11B 5/737 Physical structure of underlayer, e.g. texture
• CPC Class Codes: G11B 5/8404 manufacturing base layers

Abstract

According to one embodiment, a magnetic recording medium includes a substrate, a first underlayer formed on the substrate and including an amorphous alloy containing Ni, a crystalline second underlayer formed on the first underlayer and including simple Cr or an alloy containing Cr, and a magnetic recording layer formed on the second underlayer and including at least one element of Fe and Co and at least one element of Pt and Pd, and containing magnetic crystal grains having an L1₀ structure. An oxygen amount remaining on the upper surface of the second underlayer is larger than an oxygen amount remaining on the lower surface of the second underlayer, and a normal line to a (001) plane of the magnetic crystal grains in the magnetic recording layer is oriented with a tilt angle in a range of 3 to 25° to a normal line to a medium plane.

Claims

1. A magnetic recording medium comprising:

a substrate;

a first underlayer formed on the substrate and comprising an amorphous alloy containing Ni;

a crystalline second underlayer formed on the first underlayer and comprising simple Cr or an alloy containing Cr; and

a magnetic recording layer formed on the second underlayer and comprising at least one element of Fe and Co and at least one element of Pt and Pd, and containing magnetic crystal grains having an L1₀ structure,

wherein an oxygen amount remaining on an upper surface of the second underlayer is larger than an oxygen amount remaining on a lower surface of the second underlayer, and wherein a normal line to a (001) plane of the magnetic crystal grains in the magnetic recording layer is oriented with a tilt angle in a range of 3 to 25°

to a normal line to a medium plane.

2. The magnetic recording medium according to claim 1, wherein the amorphous alloy is selected from the group consisting of an Ni—

Nb ally, an Ni—

Ta alloy, an Ni—

Zr alloy, an Ni—

W alloy, an Ni—

Mo alloy, an Ni—

Hf alloy, and an Ni—

V alloy.

3. The magnetic recording medium according to claim 1, wherein an Ni content of the amorphous alloy is in a range of 20 to 70 at %.

4. The magnetic recording medium according to claim 1, wherein the alloy containing Cr is a Cr—

Ti alloy or a Cr—

Ru alloy.

5. The magnetic recording medium according to claim 4, wherein a Ti content of the Cr—

Ti alloy is in a range of 5 to 40 at %, and a Ru content of the Cr—

Ru alloy is in a range of 5 to 40 at %.

6. The magnetic recording medium according to claim 1, further comprising a third crystalline underlayer containing at least one element selected from the group consisting of Pt, Pd, Ag, Cu and Ir between the second underlayer and the magnetic recording layer.

7. The magnetic recording medium according to claim 6, wherein the third underlayer contains crystal grains having a (100) plane oriented with a tilt angle in a range of 3 to 25°

to the normal line to the medium plane.

8. The magnetic recording medium according to claim 1, further comprising a soft underlayer between the first underlayer and the substrate.

11. A magnetic recording apparatus comprising the magnetic recording medium according to claim 1 and a read/write head.

9. A method of manufacturing a magnetic recording medium comprising:

depositing a first underlayer comprising an amorphous alloy containing Ni on a substrate;

heating the substrate to a temperature in a range of 25 to 280°

C., followed by allowing oxygen to be adsorbed on a surface of the first underlayer;

depositing a crystalline second underlayer comprising simple Cr or an alloy containing Cr on the first underlayer having adsorbed oxygen; and

depositing a magnetic recording layer on the second underlayer, the magnetic recording layer comprising at least one element of Fe and Co and at least one element of Pt and Pd and containing magnetic crystal grains having an L1₀ structure.

10. The method according to claim 9, wherein oxygen is allowed to be adsorbed on a surface of the first underlayer so that an oxygen amount remaining on an upper surface of the second underlayer is larger than an oxygen amount remaining on a lower surface of the second underlayer.