Experimental study of thermal decay in high-density magnetic recording media

Abstract

Absiract -The thermal decay of written bits in CoCrPt/CrTi thin film media for high density longitudinal magnetic recording is examined using a magnetoresistive head at room temperature. A decay in signal output over time is observed for the media with a thin magnetic layer less than about 14 nm thick and the media noise increases. The thermal stability factor Ku.V/k.T of these media is estimated to be less than about 100. The signal decay and noise increase are more serious at higher linear recording densities. These results are consistent with the results of a micromagnetic simulation taking into account the thermal aftereffects. These characteristics suggest that media with a large magnetic anisotropy constant Ku will be required to realize high storage densities of over 10 Gbhn'.

Thermal stability in longitudinal thin film media

“…Consequently, the signal decays over time. The difference between signal decay at a low recording density and that at a high recording density is usually attributed to the effect of the demagnetization field [2], [5], [9]. Fig.…”

Thermal stability of longitudinal media for <20 Gbits/in/sup 2/ recording

“…There have been many reports of signal decay using a spin stand [19], [25]. The method we used to detect sensitivity changes in the head with time involves using a reference track that has adequately decayed.…”

Mechanism study of scratch-induced demagnetization for perpendicular magnetic disks

“…The applied load ranged from 100 to 300 lN (1.0 N = 9.8 kg/s 2 ). The scribing velocity was as slow as 0.1 mm/s, which avoids any friction-heating effect on the demagnetization (Hosoe et al 1997). Then, the scratch depth was measured by atomic force microscopy (AFM), and the demagnetization was analyzed by magnetic force microscopy (MFM).…”