COCRTA COCRPTTA DOUBLE-LAYER FILMS FOR MAGNETIC RECORDING/

This paper reports the use of CoCrTa/CoCrPtTa double-layer magnetic fi lms to produce low-noise, high-coercivity recording media. At an optim um thickness ratio, the double layer films can reach higher coercivity (H-c) than either of the single-layer films of the above alloys. The signal-to-media-noise ratio of the composite can be a few dB higher th an that of the single-layer CoCrPtTa film. Microstructure studies reve aled that the bottom-layer film not only seeds the microstructure for the upper-layer film, but also determines the noise characteristics of the double-layer film. It is suggested that the strain and exchange c oupling at the interface of the double-layer films are responsible for the enhancement of H-c.