Mohammed Gija;Alexey Dobrynin;Kevin McNeill;Mark Gubbins;Tim Mercer;Philip Bissell;Serban Lepadatu
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引用次数: 0
Abstract
Heat-assisted magnetic recording (HAMR) is a recent advancement in magnetic recording, allowing for a significant increase in the areal density capability (ADC) of hard disk drives (HDDs) compared to the perpendicular magnetic recording (PMR) technology. This is enabled by high anisotropy FePt media, which needs to be heated through its Curie temperature ($T_{C}$ ) to facilitate magnetization reversal by an electromagnetic write pole. HAMR micromagnetic modeling is, therefore, challenging, as it needs to be performed in proximity to and above $T_{C}$ , where a ferromagnet has no spontaneous magnetization. An atomistic model is an optimal solution here, as it does not require any parameter renormalization or non-physical assumptions for modeling at any temperature. However, a full-track atomistic recording model is extremely computationally expensive. Here, we demonstrate a true multiscale HAMR modeling approach, combining atomistic spin dynamics (ASD) modeling for high-temperature regions and micromagnetic modeling for lower-temperature regions, in a moving simulation window embedded within a long magnetic track. The advantages of this approach include the natural emergence of $T_{C}$ and anisotropy distributions of FePt grains. Efficient GPU optimization of the code provides very fast running times, with a 60 nm wide track of 25 20 nm long bits being recorded in several hours on a single GPU. The effects of realistic FePt L10 versus simple cubic (SC) crystal structure are discussed, with the latter providing further running time gains while keeping the advantages of the multiscale approach.
期刊介绍:
Science and technology related to the basic physics and engineering of magnetism, magnetic materials, applied magnetics, magnetic devices, and magnetic data storage. The IEEE Transactions on Magnetics publishes scholarly articles of archival value as well as tutorial expositions and critical reviews of classical subjects and topics of current interest.