US 11,138,997 B2
MULTILAYER EXCHANGE SPRING RECORDING MEDIAGeneral
US 11,138,997 B2
MULTILAYER EXCHANGE SPRING RECORDING MEDIA
Tech Center:
1700 Chemical and Materials Engineering
Examiner:
Holly Rickman
Art Unit:
1785 Miscellaneous Articles, Stock Material, Adhesive Composition, Fabrics
Agent:
MR TECHNOLOGIES, GMBH
Inventors:
Dieter Suess
Assignee:
Priority:
06/17/06
Filed:
03/19/18
Granted:
10/05/21
Expiration:
06/17/26
Abstract
A multilayer exchange spring recording media consist of a magnetically hard magnetic storage layer strongly exchange coupled to a softer nucleation host. The strong exchange coupling can be through a coupling layer or direct. The hard magnetic storage layer has a strong perpendicular anisotropy. The nucleation host consists of one or more ferromagnetic coupled layers. For a multilayer nucleation host the anisotropy increases from layer to layer. The anisotropy in the softest layer of the nucleation host can be two times smaller than that of the hard magnetic storage layer. The lateral exchange between the grains is small. The nucleation host decreases the coercive field significantly while keeping the energy barrier of the hard layer almost unchanged. The coercive field of the total structure depends on one over number of layers in the nucleation host. The invention proposes a recording media that overcomes the writeability problem of perpendicular recording media.
Cooperative Patent Classification (CPC)
B82B82Y25/00B82YG01R33/1207G01RG11B5/674G11B