The dependence of recording performance on substrate temperatures for different crystallographically oriented thin film media

Thin film media with and without a NiAl seedlayer were sputter deposited ov er a range of substrate temperatures. Two distinctly different crystallogra phic and recording performance behaviors were observed. For the samples dep osited with the NiAl seedlayer, which promotes the Co(10.0)/Cr(112) crystal lographic orientation, the media noise was relatively low and constant thro ughout the temperature range investigated, whereas there was a significant reduction in noise with increasing temperature of deposition for the conven tional media which have the Co(11.0)/Cr(200) structure. As a result an incr ease of more than 7 dB in signal-to-noise ratio was observed over the tempe rature range of 120-260 degrees C. The results suggest that the degree of C r segregation with temperatures strongly depends on grain structures, such as grain size, grain size distribution, and grain crystallographic orientat ion. Magnetic characterization of both media is correlated to their recordi ng performance as a function of substrate temperatures. (C) 1999 American I nstitute of Physics. [S0021-8979(99)50508-2].