Magnetization Switching Variations and Transition-Width Limit in Heat-Assisted Magnetic Recording

Although stability in magnetic recording usually refers to long-time (years) thermal fluctuation-induced magnetization decay, for short-time dynamic switching (microsecond to nanosecond), the stability issue is shown as magnetization switching variations. Decreased magnetic stability energy usually results in increased switching variations during magnetization reversal. This has important implications for the heat-assisted magnetic recording writing process. Here, we study magnetization switching variations for an ensemble of independent magnetic grains at elevated temperatures. Our results show that thermal fluctuation-induced magnetization switching variation is a major source of switching field distribution at elevated temperature. This inevitably results in magnetization transition width broadening and recording performance degradation. The effects of thermal fluctuation-induced switching field distribution on the recording transition-width limit are discussed.