HAMR media based on exchange bias

Abstract

In this work, we describe an alternative strategy for the development of heat assisted magnetic recording media. In our approach, the need for a storage material with a temperature dependent anisotropy and to provide a read out signal is separated so that each function can be optimised independently. This is achieved by the use of an exchange bias structure where a conventional CoCrPt-SiO2 recording layer is exchange biased to an underlayer of IrMn such that heating and cooling in the exchange field from the recording layer results in a shifted loop. This strategy requires the reorientation of the IrMn layer to allow coupling to the recording layer. This has been achieved by the use of an ultrathin (0.8 nm) layer of Co deposited beneath the IrMn layer. In this system, the information is in effect stored in the antiferromagnetic layer, and hence, there is no demagnetising field generated by the stored bits. A loop shift of 688 Oe has been achieved where both values of coercivity lie to one side of the origin and the information cannot be erased by a magnetic field.

Maximizing Zero-Field-Cooled Exchange Bias in Crystallized Co@CoO Nanocluster Assembled Thin Film by Varying Film Thickness

“…Because of the large surface-to-volume ratio in magnetic nanoparticles and hybrid magnetic nanostructures, the interfacial interactions can dominate the properties of these systems, including EB caused by the interface between different magnetic phases. − And these magnetic nanoparticles and hybrid magnetic nanostructures are of growing interest for their applications in magnetic recording media, sensitive magnetic sensors, and various biomedical applications such as drug delivery systems . Especially, EB is most often studied in thin films for their applications in the magnetic hard drive industry .…”

Giant Vertical Magnetization Shift Caused by Field-Induced Ferromagnetic Spin Reconfiguration in Ni50Mn36Ga14 Alloy

“…Since the discovery of the exchange bias effect, it has been utilized to fabricate hard disk drives, spin valves, magnetic tunnel junctions, and other "spin electronic" devices [1][2][3][4]. There are two main types of exchange bias effect research, the horizontal exchange bias effect (EB) and the vertical magnetization shift (VMS).…”

Surface and Microstructure Analysis of CoCrPt Film on RuCoCrX (X = Ti, Re) Intermediate Layers

“…The CoCrPt (oxides) perpendicular magnetic anisotropy thin films have been applied in current perpendicular magnetic recording media for long periods of time but are still required to improve the properties in the near future [1][2][3][4][5][6][7][8][9][10][11][12][13][14]. Although ordered L1 0 -FePt with higher perpendicular anisotropy has been promised for future ultra-high density heat-assisted magnetic recording media [15][16][17], improvements of the intermediate-, exchange coupling-and capping-layer are needed to optimize the magnetic properties and microstructure of CoCrPt-oxide granular films for next-generation devices.…”