Texture and angular dependence of magnetic viscosity in digital recording media

The effect of texture and angular variation on the time dependence coefficient S is studied. Magnetic measurements were made using a vibrating sample magnetometer with a resolution of 10^-5 emu. Two types of sample were examined: for the angular dependence measurements a XIDEX UK IBM 3480 data tape was used, and for the texturing study special samples of XIDEX UK TK52 tape were prepared. Increasing the degree of texture results in the variation of S with H becoming more strongly peaked around the coercive force. An increase in texture, desirable for better recording performance, is compromised by an increase in the maximum value of magnetic viscosity by a factor of two, for an increase in squareness from 0.6 to 0.8. The angular variation of the coercivities illustrated the different switching behaviors of reversible and irreversible changes of a system of single domain particles. The switching field for irreversible changes increases monotonically with angle, while the intrinsic coercivity (reversible and irreversible changes) goes through a well-defined maximum with angle