Plasmonic near-field transducer for heat-assisted magnetic recording

Plasmonic devices, made of apertures or antennas, have played significant roles in advancing the fields of optics and opto-electronics by offering subwavelength manipulation of light in the visible and near infrared frequencies. The development of heat-assisted magnetic recording (HAMR) opens up a new application of plasmonic nanostructures, where they act as near field transducers (NFTs) to locally and temporally heat a sub-diffraction-limited region in the recording medium above its Curie temperature to reduce the magnetic coercivity. This allows use of very small grain volume in the medium while still maintaining data thermal stability, and increasing storage density in the next generation hard disk drives (HDDs). In this paper, we review different plasmonic NFT designs that are promising to be applied in HAMR. We focus on the mechanisms contributing to the coupling and confinement of optical energy. We also illustrate the self-heating issue in NFT materials associated with the generation of a confined optical spot, which could result in degradation of performance and failure of components. The possibility of using alternative plasmonic materials will be discussed.