Heat-assisted magnetic recording by a near-field transducer with efficient optical energy transfer

  • An Erratum to this article was published on 01 May 2009


Although near-field microscopy has allowed optical imaging with sub-20 nm resolution, the optical throughput of this technique is notoriously small. As a result, applications such as optical data storage have been impractical. However, with an optimized near-field transducer design, we show that optical energy can be transferred efficiently to a lossy metallic medium and yet remain confined in a spot that is much smaller than the diffraction limit. Such a transducer was integrated into a recording head and flown over a magnetic recording medium on a rotating disk. Optical power from a semiconductor laser at a wavelength of 830 nm was efficiently coupled by the transducer into the medium to heat a 70-nm track above the Curie point in nanoseconds and record data at an areal density of 375 Tb m−2. This transducer design should scale to even smaller optical spots.

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Figure 1: Diagram of the NFT and its position in the PSIM.
Figure 2: NFT coupling efficiency and field intensity.
Figure 3: Integrated recording head.
Figure 4: SEM images of the NFT.
Figure 5: MFM image of a recorded track.
Figure 6: Cross track scan of recorded data.

Change history

  • 24 March 2009

    In the version of this article originally published, in the caption to Fig. 4a the unit given for the distance between the dashed lines was incorrect. The error has now been corrected in the HTML and PDF versions.


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The authors would like to thank many colleagues at Seagate Research who supported this work, including C. Hardie, R. Hempstead, J. Keily, M. Kryder, L. Lee, C. Mihalcea, T. Morkved, K. Pelhos, T. Rausch, M. Re, K. Sendur and M. Xiao. Part of this work was performed under the INSIC HAMR ATP Program, with the support of the US Department of Commerce, National Institute of Standards and Technology, Advanced Technology Program, Cooperative Agreement Number 70NANB1H3056.

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Correspondence to W. A. Challener.

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Challener, W., Peng, C., Itagi, A. et al. Heat-assisted magnetic recording by a near-field transducer with efficient optical energy transfer. Nature Photon 3, 220–224 (2009). https://doi.org/10.1038/nphoton.2009.26

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