Perpendicular magnetic recording medium

Patent metadata

Field	Value
Publication number	US-10020016-B2
Application number	US-201415035670-A
Country	US
Kind code	B2
Filing date	Dec 2, 2014
Priority date	Dec 10, 2013
Publication date	Jul 10, 2018
Grant date	Jul 10, 2018

Abstract

A magnetic recording medium including a magnetic recording layer of a granular structure and having a large thickness as well as excellent magnetic properties is provided. The perpendicular magnetic recording medium includes a non-magnetic substrate and a magnetic recording layer, wherein the magnetic recording layer includes first magnetic recording layers on the side of the non-magnetic substrate and second magnetic recording layers, the first magnetic layers have a granular structure including first magnetic crystal grains containing an ordered alloy and a first non-magnetic segregant surrounding the first magnetic crystal grains and containing carbon; and the second magnetic layers have a granular structure including second magnetic crystal grains containing an ordered alloy and a second non-magnetic segregant surrounding the second magnetic crystal grains and containing Zn and O.

First claim

The invention claimed is:

1. A perpendicular magnetic recording medium comprising a non-magnetic substrate and a magnetic recording layer, wherein:
the magnetic recording layer consists essentially of one or more first magnetic layers and one or more second magnetic layers;
the one or more first magnetic layers are odd-numbered layers from the non-magnetic substrate;
the one or more second magnetic layers are even-numbered layers from the non-magnetic substrate;
the one or more first magnetic layers have a granular structure comprising first magnetic crystal grains comprising an ordered alloy and a first non-magnetic segregant surrounding the first magnetic crystal grains and comprising carbon;
the one or more second magnetic layers have a granular structure comprising second magnetic crystal grains comprising an ordered alloy and a second non-magnetic segregant surrounding the second magnetic crystal grains and comprising Zn and O; and
the magnetic recording layer has a total thickness of 5 nm or more.

2. The magnetic recording medium according to claim 1 , wherein the magnetic recording layer has a two-layered structure consisting of one of the first magnetic layers and one of the second magnetic layers.

3. The magnetic recording medium according to claim 1 , wherein the magnetic recording layer has a three-layered structure consisting of two of the first magnetic layers and one of the second magnetic layers.

4. The magnetic recording medium according to claim 3 , wherein the ordered alloy in the first magnetic layer is FePt, the first non-magnetic segregant is carbon, the ordered alloy in the second magnetic layer is FePt, and the second non-magnetic segregant is ZnO.

5. The magnetic recording medium according to claim 1 , wherein the second non-magnetic segregant constitutes 10% by volume or more and 50% by volume or less of the second magnetic layer.

6. The magnetic recording medium according to claim 5 , wherein the ordered alloy of the first magnetic layers and the ordered alloy of the second magnetic layers are an alloy comprising at least one element selected from the group consisting of Fe and Co, and at least one element selected from the group consisting of Pt, Pd, Au and Ir.

7. The magnetic recording medium according to claim 6 , wherein the ordered alloy of the first magnetic layers and the ordered alloy of the second magnetic layers are selected from the group consisting of FePt, CoPt, FePd and CoPd.

8. The magnetic recording medium according to claim 1 , wherein the first magnetic layers have a thickness of 0.5 to 4 nm, and the second magnetic layers have a thickness of 1 to 20 nm.

9. The magnetic recording medium according to claim 1 , wherein the first magnetic crystal grains and the second magnetic crystal grains are composed from the same constituent elements.

10. The magnetic recording medium according to claim 1 , further comprising one or more layers selected from a heat sink layer, an adhesive layer, a soft-magnetic under layer, an interlayer, and a seed layer.

11. The magnetic recording medium according to claim 1 , wherein the first magnetic layers have a thickness in a range from 1 nm to 2 nm.

Assignees

• Fuji Electric Co Ltd

Inventors

• Uchida Shinji
• Shimatsu Takehito

Classifications

• G11B5/82

  Disk carriers · CPC title

• G11B5/653

  containing Fe or Ni (containing Co G11B5/656; containing inorganic, non-oxide compounds of Si, N, P, B, H or C G11B5/657; containing oxygen G11B5/658) · CPC title

• G11B5/65

  characterised by its composition (G11B5/66 takes precedence) · CPC title

• G11B5/656

  containing Co (containing inorganic, non-oxide compounds of Si, N, P, B, H or C G11B5/657; containing oxygen G11B5/658) · CPC title

• G11B5/667

  including a soft magnetic layer · CPC title