Three-dimensional computation of the field of magnetic recording heads

A new numerical technique for computing the three-dimensional magnetic field of a recording head is presented: the "magnetic-field surface-integral equation method". It is based on a vector Green-type integral relation for the magnetic-field strength. The present implementation applies to a recording head configuration consisting of infinitely permeable magnetic materials, perfectly conducting electric shields and a coil, all of arbitrary size and shape. The method is applied to a cubical head with and without magnetic or electric side shields. It is concluded that near the head's sides the harmonic response shows higher long wavelength amplitude oscillations than near the center of the head. The presence of a magnetic side shield is found to decrease considerably the side field, whereas an electric shield, even when perfectly conducting, is much less effective.