Media design for three-dimensional heat-assisted magnetic recording

We design media for three-dimensional heat-assisted magnetic recording at 2 Tbpsi (total density of 4 Tbpsi), taking account of heat transfer simulation, field calculation, and information stability in high Curie temperature (HC) and low Curie temperature (LC) layers. The medium surface temperature while writing in the HC layer, the thermal gradients while writing in the HC and LC layers, and the grain temperature difference between the HC and LC layers while writing in the LC layer are discussed by using a heat transfer simulation. The magnetic field strength as a function of distance from the layer surface for a single layer is discussed by employing a field calculation. The Curie temperatures of TLC and THC, and the grain heights of hLC and hHC in the LC and HC layers, respectively, are also discussed in terms of information stability during 10 years of archiving and writing in the LC layer. As a result, a media structure is decided whereby the upper, namely, the surface layer is an LC layer with TLC = 625 K and hLC = 4.5 nm, and the lower layer is an HC layer with THC = 750 K and hHC = 6.0 nm with an anisotropy constant ratio of 0.8. © 2020, Magnetics Society of Japan. All rights reserved.