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.