DEPENDENCE OF MEDIA NOISE ON GRAIN-SIZE AND INTERGRANULAR COUPLING INTHIN-FILM MEDIA

The media noise performance is discussed in connection with grain size and intergranular coupling for the Co85.5Cr10.5Ta4, Co78Cr17Ta5, and Co62.5Ni30Cr7.5 thin-film media fabricated under the ultraclean sputte ring process (UC process). It is claified that the value of S/N-m is q uantitatively represented as functions of the value of H-c/H-k(grain) and the grain size in every kind of media. The value of signal-to-medi a noise ratio (S/N-m) increases with the increment in H-c/H-k(grain) a nd also with the decrement in grain size. In the media with grains ade quately separated by segregated grain boundaries fabricated by the UC process, grain-size reduction, taking account of the decrease in inter granular magnetostatic coupling, is required to obtain even higher S/N -m values. (C) 1996 American Institute of Physics.