The effect of surface roughness on the head-tape interface

The effect of rape surface roughness on the head-tape interface is investigated for typical head contours using tapes with different surface roughness characteristics. Intensity-based monochromatic interferometry is used to obtain the asperity compliance curves for tapes of different roughness by relating contact pressure to the spacing between the head and the tape. A parabolic model and the Greenwood-Williamson model for contact between rough surfaces are used to ''curve fit'' experimental results for contact pressure versus spacing, and numerical calculations for the head-tape spacing of a cylindrical head with and without transverse slots are presented for two tapes with different roughness characteristics. The numerical calculations for the head-rape spacing are compared with experimental measurements showing excellent agreement between numerical and experimental results. It is concluded that the head-tape spacing for high recording density applications is limited by tape surface roughness.