Setting Write Spacing in Heat Assisted Magnetic Recording

Heat assisted magnetic recording (HAMR) has the potential to deliver higher storage areal density beyond 1 Tb/in
²
. 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.