Track width measurement in heat-assisted magnetic recording systems using the cross-track DC noise method

Abstract

Abstract This paper uses a cross-track DC noise measurement technique to determine the written track width in heat-assisted magnetic recording (HAMR). The method is approached as a simple, no-extra-hardware-required technique on a spin-stand to determine the written track width as well as the DC noise amplitude at the center track in a HAMR system. The track width data show the expected trends with changing laser operating current ( I o p ) and write current ( I w ), and they are strongly correlated with track density capabilities and physical near-field transducer (NFT) peg width. The written track width is essentially defined by the I o p , which increases as I o p increases. The method is useful for comparing the magnetic responses of different writer pole or NFT peg geometries, as well as media design comparison to provide insight into the head/component necessary to improve HAMR system performance, which is useful HAMR recording parameters for head/media designers and test engineers.