The coupling effect between the dual elements of a superimposed head

The pole-tip and gap-geometry design of a single-element thin-film head is always a compromise between providing sufficient write field and fine spatial resolution. The write and read functions of a dual element can be optimized separately with the added degree of freedom. The pole-tip and gap thickness, pole-tip width, and the head material can be different for the two write and read elements. This paper describes the fabrication of superimposed dual-element thin-film heads, experimental and computer simulation results of the magnetic recording characteristics of such heads. Specifically, it was observed that there is a coupling effect between the two elements of a superimposed head. The coupling effect manifests itself in a minor pulse in addition to the major pulse over an isolated transition, and the ripples in the amplitude vs. frequency curve. The experimental characterization of the coupling effect was compared with computer simulation models and the agreement is good. The impact of the coupling effect on data-handling capability is still under investigation.