Numerical analysis of writing and reading with multiturn film heads

The effect of various parameters (film thickness, pole-face length, gap length, throat height, permeability, number of turns) on performance (resolution, peak shift, efficiency, saturation current) of multiturn film heads has been investigated using a numerical solution of the integral form of Maxwell´s equations. It is found that very small throat heights are required not only to achieve adequate efficiency, but also to prevent saturation at currents lower than the required write current. Gap length and pole-face length are the critical dimensions which control resolution and peak shift.