High Density Heat-Assisted Magnetic Recording Media and Advanced Characterization—Progress and Challenges

Heat-assisted magnetic recording (HAMR) is being developed as the next generation magnetic recording technology. Critical components of this technology, such as plasmonic near-field transducer (NFT) and high anisotropy granular FePt media, as well as the performance and reliability of fully integrated drives have been reported. This paper will focus on the progress and challenges of HAMR media, including microstructure and thermal design as well as the testing and characterization at high field and high temperature. Due to the importance of the Curie temperature distribution, σT_C, for HAMR, we present a newly developed temperature-dependent complex ac susceptibility method to extract σT_C for HAMR media. Such novel magnetic characterization methods have been used in combination with other high field magnetic metrology and spin-stand recording to provide feedback for continuous improvements of HAMR media. Together with NFT and write head design, the thermal design, σT_C, and microstructure of the media are key factors to reduce the transition jitter below 2 nm as demonstrated in a previously reported 1 Tb/in² HAMR demonstration. Here, we report the further improvements by significantly enabling higher linear density (>2500 kfci) HAMR and steady progress in areal density to 1.402 Tb/in².