in a narrow track head about three microns wide we believe that approximately one oersted is near the high end of an acceptable coercivity level for a narrow track e g three microns read write head but the actual desirable value will depend upon specific widths and applications for purposes of the present invention the acceptable level of coercivity for a given geometry may be defined as that level which permits a transverse at rest domain state orientation to resume prior to reading when cycling between reading and writing we have found that increasing the magnetic anisotropy field relative to an acceptable level of coercivity i e h k relative to h c in an alloy magnetic head improves the w c w t ratio thus to better assure achieving the domain configuration of fig1 a hence if the ratio of h k h c is kept relatively high with h k and h c at acceptable levels discussed below then the domain structure of fig1 a can be obtained we have recognized that the h k h c ratio can be favorably controlled more specifically we have found that as cobalt is added to a nickel iron alloy both the h c and h k increase although at different rates this can be discerned from a comparison of graphs 2a and 2b in graph 2a h c in oersteds is plotted as a function of weight percent of cobalt in the deposited.