Effect of perpendicular magnetic recording media nucleation field on thermal stability

Abstract

We developed a new component level thermal decay test that directly measures decays in media signal and noise, which are combined to obtain signal-to-noise ratio (SNR) decay. The SNR decay on spin stand is in good agreement with the hard disk drive bit error rate decay data. The effect of recording linear density (KFCI) on the SNR decay is studied, which is mainly attributed to the demagnetization field change with the recording density. Applying this test to a group of media with a broad range of nucleation field (Hn), it is found that the SNR decay correlates better with the Hn than with the thermal stability factor (KuV/kBT). For a perpendicular magnetic recording media with Hn∼−2000 Oe exhibits zero SNR decay, it indicates strong robustness thermal stability.

Correlation of ATI and SNR Decay in Magnetic Recording

“…Bulk magnetic properties of the disk media A, B, and C are tabulated in Table II. The nucleation field is a critical media parameter linked to demagnetization field and SNR decay [10]. SNR decay is measured at 141 KFCI which is set to be less than the HDD servo writing frequency and the perpendicular OW (over write) frequency.…”