Heat-assisted magnetic recording (HAMR) has been considered as a promising technique for the next-generation magnetic recording. The light delivery system of HAMR can generate a tightly focused optical spot to heat the magnetic media. A HAMR magnetic medium, offering a high anisotropy field for stable recorded at room temperature, can be temporarily heated over the Curie temperature by the optical spot for lowering the media coercivity. Data bits can be written to magnetic media successfully by the magnetic field head when the coercivity is reduced sufficiently. For the most current designs of HAMRs, the efficiency is mostly in the range of 2%- 8%. The current light system still suffers from the low field enhancement of the light spot or the low absorption efficiency of the magnetic media.
The team of Prof. Chen Jincai proposed a novel light delivery system to improve the absorption efficiency. The relevant research results were recently published in the top-level journal of magnetic recording, IEEE Trans. Magn. (namely TMAG), entitled “High Field Enhancement of Plasmonics Antenna Using Ring Resonator for HAMR” by W. Chen, J. Chen, Z. Gan, K. Luo, Z. Huang and P. Lu (https://ieeexplore.ieee.org/document/9082031), and the paper has been selected to be on the Front Cover of the July TMAG issue. The ring resonators reported in this paper as the novel system can improve the absorption efficiency of magnetic media more than half. The advantage of ring resonators is that the enhanced internal field in the ring resonator can be improved several times at critical coupling conditions by controlling the attenuation of the field in the ring waveguide. The enhanced internal field of ring resonators can be used for excitation of the strong field of NFT. The energy of the laser has been confined in the ring and can be recycled to excite the surface plasmon polaritons (SPP), which can lower the requirement of the laser power.
In addition, the team of Prof. Chen Jincai has systematically studied the ultra-high density two-dimensional magnetic recording, including the signal joint detection algorithm of multi-head array, the coding & decoding algorithm based on neural network, and the optimization design method of writing head, which provides theoretical and technical support for the realization of ultra-high-density magnetic recording. A number of related achievements have been published in high-level international journals and conferences in the magnetic recording field.
