The Role of Media Property Distribution in HAMR SNR

Generally distributions in anisotropy field and grain-to-grain exchange are considered to be the main sources of noise in heat assisted magnetic recording (HAMR). Through systematic micromagnetic modeling based upon the Landau-Lifshitz-Bloch (LLB) equation, however, we show that variation in the Curie temperature from grain-to-grain is the primary contributor to noise in HAMR. Additionally, small and narrowly-distributed exchange coupling turns out to be helpful under certain circumstances or changes the noise format. These could be explained by the recently proposed HAMR noise mechanism and related recording patterns.