Reversal in Bit Patterned Media With Vertical and Lateral Exchange

Abstract

The extent to which dipolar interactions affect switching field distributions and thermal stability, and subsequently system performance, depends closely on the areal density, materials properties, and the architecture of the media, as well as the recording scheme and field profiles. This paper assesses, via micromagnetic simulations, the potential of heterogeneous capped bit patterned media and other proposed patterned media designs for ultra-high-density magnetic recording with respect to writability, switching field distributions, and thermal stability at different areal densities. Such media is comprised of an array of homogeneous or exchange coupled composite elements with vertical anisotropy that is ferromagnetically or antiferromagnetically coupled to a continuous horizontal layer. It is shown that such systems, characterized by lateral and vertical exchange, enable ultra-high-density recording at low switching fields while ensuring high thermal stability and low switching field distributions. Mechanisms leading to improved performance in capped systems are investigated. Structural and material considerations are provided for all media models.