CoCrTa/CoCrPtTa double-layer films for magnetic recording

Reports the use of CoCrTa/CoCrPtTa double-layer magnetic films to produce low-noise, high-coercivity recording media. At an optimum thickness ratio, the double layer films can reach higher coercivity (H/sub 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 than that of single-layer CoCrPtTa film. Microstructure studies revealed 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 coupling at the interface of the double-layer films are responsible for the enhancement of H/sub c/.