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'.

Articles you may be interested inMicrostructure and magnetic properties of Co Cr Pt -Si O 2 perpendicular recording media with synthetic nucleation layers

We have investigated the capability of dual oxide by comparing the magnetic and recording characteristics of CoCrPt-oxide media with SiO 2 , TiO 2 , or a mixture of SiO 2 and TiO 2 . We found that CoCrPt-oxide films with a mixture of SiO 2 and TiO 2 have a higher coercivity, particularly at a low O 2 partial pressure, than CoCrPt-oxide films with SiO 2 or TiO 2 . Media with SiO 2 or a mixture of SiO 2 and TiO 2 have a higher signal-to-noise ratio (SNR) than that of media with TiO 2 . The high SNR of the media with a mixture of SiO 2 and TiO 2 was obtained in narrower magnetic-core-width conditions than those of the media with SiO 2 , suggesting that the dual oxide media have greater potential for areal density growth than the single oxide media. Transmission electron microscopy revealed that the dual oxide film has narrower and more uniform grain boundaries than the single oxide films. We believe that these microstructures will lead to higher packing density with reduced dispersion of intergranular exchange coupling, which is one possible reason for the improved recording performance.

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