Optimizing Modeled ECC Media Structures for MAMR

We present micromagnetic simulations at various grain sizes of four-layer exchange-coupled composite microwave-assisted magnetic recording (MAMR) systems that have maximized areal density capability using the Nelder-Mead simplex algorithm. We restrict our media to have crystalline KuV/kT > ~100. Our optimized MAMR designs show roughly 120 Gb/in 2 areal density growth per nanometer of grain pitch reduction and achieve an areal density of 37% larger than a publicly available 700 Gb/in 2 conventional perpendicular recording reference at a similar grain size and write width. We analyze all 26 optimization variables to identify common trends indicative of high-performance MAMR media. Our principle goal is to help media designers optimize media for MAMR performance, and to project how this optimization changes with the grain size. Balancing write-ability, noise performance, thermal stability, and resonance-matching characteristics is most important.