McDermott, Will & Emery
Texture-induced magnetic anisotropy of soft underlayers for perpendicular recording media
Perpendicular magnetic recording media having no, or substantially reduced, Barkhausen noise are manufactured by a method comprising steps of:(a) providing a non-magnetic substrate having a surface;(b) providing the surface of the substrate with a unidirectional texture pattern;(c) forming an underlayer of a soft magnetic material over the unidirectional texture pattern, the layer of soft magnetic material having positive magnetostriction and uniaxial magnetic anisotropy and including a multiplicity of magnetic domains; and(d) forming a magnetic recording layer of a hard magnetic material over the underlayer;wherein the uniaxial magnetic anisotropy of the underlayer of soft magnetic material is sufficiently large to orient the magnetic domains thereof along the axis of the uniaxial magnetic anisotropy and thereby restrict domain wall formation and/or movement, whereby generation of Barkhausen noise in the soft underlayer is suppressed.
Seagate Technology LLC
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Chung-Hee Rajiv Yadav
Chang Ranjan