Analysis of thin film heads with a generalized transmission line model

A generalized transmission line model is presented to analyze a multiturn thin film head with fanned-out rear poles, thinner pole tips, and a spiral coil enclosing a rear flux closure, which could be narrower than the poles. The problem is formulated with two-dimensional (2D) partial differential equations and solved by the finite element method. The head efficiency, head inductance, and field distribution in the pole are computed for various geometries of rear flux closures and coils. The region of head saturation may also be found. Proper design of the width of the rear flux closure may greatly increase the writing current at the onset of head saturation. The ease of anisotropic permeability is also analyzed, and very little effect on the head performance is shown.