R&D: Track Width Measurement in HAMR Using Cross-Track DC Noise Method

Japanese Journal of Applied Physics has published an article written by Prasit Kampun, College of Advanced Manufacturing Innovation, King Mongkut’s Institute of Technology Ladkrabang, Bangkok, 10520, Thailand, Lertsak Lekawat, King Mongkut’s Institute of Technology Ladkrabang, Bangkok, Thailand, and Damrongsak Tongsomporn, Seagate Technology Thailand Ltd, Samut Prakan, Thailand.

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_op) and write current (I_w), and they are strongly correlated with track density (TD) capabilities and physical near-field transducer (NFT) Peg width. The written track width is essentially defined by the I_op, which increases as I_op 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.“