R&D: Setting Write Spacing in HAMR

IEEE Transactions on Magnetics has published an article written by Shaomin Xiong, Robert Smith, Staging and Research, Recording Subsystems, Western Digital Company, San Jose, CA 95119 USA, Jian Xu, Shuji Nishida, Masaru Furukawa, Kenji Tasaka, Kenji Kuroki, Staging Integration, Recording Subsystems, Western Digital Company, Fujisawa 252-0888, Japan, Yeoungchin Yoon, Na Wang, Sripathi Canchi, Erhard Schreck, Qing Dai, Staging and Research, Recording Subsystems, Western Digital Company, San Jose, CA 95119 USA.

Abstract: “Heat assisted magnetic recording (HAMR) has the potential to deliver higher storage areal density beyond 1 Tb/in². A laser is integrated in the flying read/write head to heat up the magnetic media using a near field transducer (NFT). A large portion of the laser energy is absorbed inside the head, resulting in elevated temperature around the NFT. Thermal protrusions of different magnitudes and time scales occur after turning on the laser. These laser heating-induced protrusions must be characterized for each head and compensated in HAMR drives. In this paper, a magnetic recording-based method is proposed to perform in situ protrusion measurements and assist in setting the write spacing. This method has been successfully demonstrated on the spinstand and implemented into HAMR drives.“