High anisotropy CoCrPt(B) media for perpendicular magnetic recording

Abstract

CoCrPt(B) media with high magnetic anisotropy have been fabricated at a thin magnetic layer thickness (10 nm) and a thin interlayer thickness (4 nm). The hard magnetic properties of the CoCrPt enable addition of boron, which aids to magnetically decouple the grains. These media are thermally stable and have an enhanced signal-to-noise ratio.

Coherent vs. incoherent switching for elongated CoPt–O grains in high-anisotropy medium

“…This dramatic increase was enabled by continuous improvements of media, heads and other recording subsystems. The media, in particular, are comprised of weakly exchange coupled magnetic grains with average size (D) of 7-8 nm at 100 Gbit/in 2 [1][2][3]. Designs to achieve 1 Tbit/in 2 require grain sizes as small as 4-5 nm [4,5].…”

Magnetic reversal and domain structure in perpendicular AF-coupled films

“…In current implementations the coupled layers have their moment within the film plane. However, as lateral dimensions continue to shrink it may become advantageous to design devices with the moments out of the plane [6][7][8]. This is certainly the case for recording media, where perpendicular recording is being actively pursued [8].…”

Applied Trends in Magnetic Rare Earth/Transition Metal Alloys and Multilayers

“…Therefore, the focus moved from traditional materials such as FePd or CoCrPt to materials with high magneto-crystalline anisotropy as CoPt or SmCo 5 [ 15 ]. Sometimes these alloys can benefit from the addition of other elements, such as Cr and B on CoPt, that segregate and favor the creation of smaller bits and therefore higher recording densities [ 16 ]. RE–TM alloys are of interest because, as we will see below, they might help to increase the magnetic anisotropy and facilitate PMA.…”