Patterned media bits with cladding shell
AssigneeSeagate Technology LLC
InventorsHaiwen Xi, Kaizhong Gao, Song S. Xue
Life of this patent
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Abstract
A bit patterned media (BPM) includes many magnetic dots arranged in tracks on a substrate. The magnetic dots each have a hard magnetic core, a soft magnetic cladding surrounding the core and a thin non-magnetic layer that separates the hard magnetic core from the soft magnetic ring. The soft magnetic cladding stabilizes the magnetization at the edges of the hard magnetic core to improve the signal to noise ratio of the magnetic dots. The soft magnetic rings also narrow the magnetic field of the dots which reduces the space requirements and allows more dots to be placed on the substrate.
Claims20
A magnetic storage device, comprising,
- a plurality of spaced apart magnetic bits, each bit constituting a discrete magnetic domain on a planar surface, each bit comprises a hard magnetic core with an external surface, a non-magnetic spacer laterally in contact with the external surface of the core and a magnetically soft cladding surrounding the non-magnetic spacer wherein the non-magnetic spacer and the soft magnetic cladding are configured such that the hard magnetic core and the soft magnetic cladding are operable to anti-ferromagnetically couple with each other.
A method, comprising:
- on a planar surface of a substrate, forming a plurality of spaced apart magnetic bits, each bit comprising a hard magnetic core with a first magnetization direction perpendicular to the plane surface;
- forming a thin non-magnetic spacer layer around a lateral surface of each of the hard magnetic cores;
- and
- forming a soft magnetic cladding disposed around a lateral surface of each of the space layers, the magnetic cladding having a second magnetization direction perpendicular to the planar surface and opposite of the first direction.
A magnetic storage device, comprising:
- a magnetic bit comprising:
- a hard magnetic core with an external surface;
- a non-magnetic spacer laterally in contact with the external surface of the hard magnetic core;
- and
- a soft magnetic cladding surrounding the thin non-magnetic spacer;
- wherein the non-magnetic spacer and the soft magnetic cladding are configured such that the hard magnetic core and the soft magnetic cladding are operable to anti-ferromagnetically couple with each other.
Dependencies are inferred from the claim text.