Magnetic write field is a critical factor in determining the quality of the magnetic write transitions, which determine the linear density (LD) limit in heat-assisted magnetic recording (HAMR). We introduce a reversed DC band approach as a simple, no extra-hardware-Required technique in a spin-stand to assess the magnetic write field ( ) contributions, independently in an HAMR system. Heads with different distances between near-field transducer and writer pole, and media with and without soft magnetic under layer were characterized. The estimated result strongly correlates with LD and signal-to-noise ratio, which agrees with previous modeling studies. These results give insight into the head/component required to optimize the HAMR’s system performance. The technique provides qualitative ranking of magnetic write fields and recording temperature, as well as laser operating current at Curie temperature for head/component designs.

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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.