US 9,542,967 B2Granted

Magnetic recording medium

AssigneeSony Corporation

InventorsNoboru Sekiguchi, Tomoe Ozaki, Junichi Tachibana

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Abstract

There is provided a magnetic recording medium including a surface having a longitudinal direction and a lateral direction. An arithmetic average roughness Ra, a ratio PSDMD,short/PSDTD,short, and a ratio PSDMD,long/PSDTD,long on the surface satisfy Ra≦3.0 nm, PSDMD,short/PSDTD,short≦0.65, and 1.3≦PSDMD,long/PSDTD,long≦2.3, in which PSDMD,short is an average value of PSD values in a range from 0.15 μm to 0.4 μm in the longitudinal direction of the surface, PSDTD,short is an average value of PSD values in a range from 0.15 μm to 0.4 μm in the lateral direction of the surface, PSDMD,long is an average value of PSD values in a range from 0.4 μm to 5.0 μm in the longitudinal direction of the surface, and PSDTD,long is an average value of PSD values in a range from 0.4 μm to 5.0 μm in the lateral direction of the surface.

Claims20

Dependent claims

A magnetic recording medium comprising:

a surface having a longitudinal direction and a lateral direction,
wherein an arithmetic average roughness Ra, a ratio PSDMD,short/PSDTD,short, and a ratio PSDMD,long/PSDTD,long on the surface satisfy the following relational expressions
Ra≦3.0 nm,
PSDMD,short/PSDTD,short≦0.65, and
1.3≦PSDMD,long/PSDTD,long≦2.3,
wherein PSDMD,short is an average value of PSD values in a range of 0.15 μm or more and 0.4 μm or less in the longitudinal direction of the surface, PSDTD,short is an average value of PSD values in a range of 0.15 μm or more and 0.4 μm or less in the lateral direction of the surface, PSDMD,long is an average value of PSD values in a range of 0.4 μm or more and 5.0 μm or less in the longitudinal direction of the surface, and PSDTD,long is an average value of PSD values in a range of 0.4 μm or more and 5.0 μm or less in the lateral direction of the surface.

3 more elements

Dependencies are inferred from the claim text.

Facts

Application: 14/568,423Filed 12 Dec 2014
Priority: JP 2014-0012337 Jan 2014
Published: US 2015/0194174 A19 Jul 2015
Granted: 10 Jan 2017
Term ends: Not estimatedThe source records don’t support an estimate.

Classification7 codes

G11B 5/7369
Non-polymeric layer under the lowermost magnetic recording layer: two or more non-magnetic underlayers, e.g. seed layers or barrier layers
G11B 5/658
Characterised by its composition: containing oxygen, e.g. molecular oxygen or magnetic oxide
G11B 5/667
The record carriers consisting of several layers: including a soft magnetic layer
G11B 5/676
The record carriers consisting of several layers: having magnetic layers separated by a nonmagnetic layer, e.g. antiferromagnetic layer, Cu layer…