Role of FePt grain size on writing performance for next-generation magnetic recording technology

Heat-assisted magnetic recording (HAMR) and heated dot magnetic recording (HDMR) technologies are promising data storage solutions proposed to increase the areal density (AD) beyond 4 [Formula: see text]. However, there is a possibility of "back-switching" of the recorded data due to the thermally induced fluctuations at the elevated recording temperature, which can lead to an increased bit error rate (BER) in HAMR/HDMR. In this work, we investigate the effects of crucial parameters such as writing time, writing field, and damping constant on writing performance, particularly in relation to AD and BER. The atomistic spin model, implemented via the VAMPIRE software package, is employed to analyze the dynamics of the magnetization switching process, enabling the calculation of BER. We also propose a master equation model for calculating magnetization cooling curves that aligns with numerical simulations. Our results show that magnetic grains with a diameter of 5 nm are suitable for increasing areal density, achieving an AD of 16.4 [Formula: see text]. However, smaller grains with diameters of 3 nm and 4 nm, although providing a higher areal density than the 5 nm grains, exhibit a higher BER. Interestingly, for the system with high AD the BER can be reduced by applying a higher writing field and longer writing time or selecting a storage medium with high damping constant. This study demonstrates how to optimize key factors to enhance the writing performance in HAMR and HDMR technologies.