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

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 Gb/in²