TOPOGRAPHICALLY CONTROLLED ANISOTROPY IN SANDWICH VIDEO HEADS

The performance of sandwich heads for high-density video recording can be improved if the soft magnetic layer is given a special profile, Th is is achieved by sputter deposition of amorphous Co films on substrat e tiles that have a grooved surface profile. On the basis of a conside ration of the relevant energy terms the critical groove dimensions are estimated, The effect of surface topography on the relative permeabil ity is verified from test structures on strips and ring-shaped substra tes. Sandwich heads, manufactured with a groove pattern distributed ra dially around the coil chamber, perform 3-4 dB better than conventiona l heads, This demonstrates the feasibility of topographic anisotropy c ontrol.