Study of Erase Band and Write Performance in Shingled Mag-netic Recording with Exchanged Coupled Composite Media

The shingled magnetic recording (SMR) with $L 1 _{0} -$FePt based exchange coupled composite (ECC) media is a promising way to achieve ultra-high recording density [1], [2]. With the increasing track density, shingled writing inevitably causes the adjacent tracks erasure (ATE) and corresponding erase band noise (EBN), which deteriorates the write performance and introduces more write errors. During the shingled write process, our study indicates the skew and corner angles of wide main pole affect the EBN, moreover the insensitive angular dependence of switching field of ECC media is found to play an important role in mitigating transition noise and ATE [2]. Compared to our previous digest presented in Intermag2015 [3], this paper improves the calculation method of erase band width (EBW) by considering the overwriting side in SMR, more importantly the impact of ECC media on mitigating ATE is explored with EBW and bit error rate. Furthermore, the shingled write heads with different corner angle $(CA)$, tip tapered angle $(TA)$ and skew angle $(SA)$ are studied to reach a tradeoff between adequate write field and moderate EBW. The investigation indicated that the combination of relatively smaller CA, larger TA and smaller SA was beneficial for reducing the EBN, while it weakened the write field. Hence we suggested that an optimized writer design $(CA = 78 ^{circ}$, $TA = 50 ^{circ}$, $- 10 ^{circ} < SA < 10 ^{circ}$ in our simulation) with ECC media $L 1 _{0} -$FePt(6nm)/ [Co/Ni]
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(4 nm) could provide adequate write field and minimize the EBN simultaneously.