Characterization of near field transducers for high density heat assisted magnetic recording combined with FePt recording media

This paper presents a thorough experimental analysis of the use of nano-apertures as near field transducers (NFT) with FePt as a magnetic material in the near field. C-shaped nano-apertures can be used an efficient near field transducer (NFT) in heat assisted magnetic recording (HAMR). As the recording medium in HAMR recording is a magnetic material, the interaction of optical fields with a NFT will be different compared to the situation of a NFT in isolation. To the best of our knowledge, this is the first study to explore the impact of magnetic media proximity on efficiency and optical characteristics of NFTs experimentally. Different shaped nano-apertures including “C”, “I”, and square nano-apertures having equal areas were fabricated in a gold layer deposited on a SiO₂ substrate. We have compared the transmission characteristics of all these nano-apertures and have studied the localized plasmonic effect causing high optical transmission in “C” and “I” shaped nano-apertures as compared to square nano-apertures.