The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Sep. 21, 2010
Filed:
Feb. 01, 2008
Ryoichi Mukai, Kawasaki, JP;
Ryoichi Mukai, Kawasaki, JP;
Showa Denko K.K., Tokyo, JP;
Abstract
A perpendicular magnetic recording medium comprises a soft-magnetic backing layer formed on a substrate, an orientation control layer formed on the soft-magnetic backing layer, a first foundation layer of a continuous film of Ru or a Ru alloy formed on the orientation control layer, a second foundation layer including a plurality of crystal grains of Ru or a Ru alloy formed on the first foundation layer with a gap separating the plurality of crystal grains from each other, and a recording layer including a plurality of magnetic particles formed on the second foundation layer respectively in correspondence to the plurality of crystal grains, each of the magnetic particles having an easy axis of magnetization in a direction generally perpendicular to a substrate surface, and a non-magnetic grain boundary phase isolating said plurality of magnetic particles from each other, wherein the first foundation layer comprises a plurality of crystal grains formed in contact with each other at respective grain boundaries, one of the plurality of crystal grains constituting the second foundation layer being formed in correspondence to one of the plurality of crystal grains constituting the first foundation layer, and wherein there are provided a plurality of nuclei at an interface between the crystal grain of the second foundation layer corresponding to the one crystal grain of the plurality of crystal grains constituting the first foundation layer and the orientation control layer.