High-resolution magnetic field measurement system for recording heads and disks

A high-resolution system for measuring the magnetic fields near recording heads and disks has been built. The perpendicular field components close to the head and disk surfaces are measured with an InSb Hall probe which is moved point-by-point under computer control. The computer also records the magnetic field strength as a function of position in a plane parallel to the head or disk surface. The active area of the probe is 2x2 microm and a roughly 1-microm separation between the probe and the surfaces being measured can be obtained. Measurements of the fields near transitions on a particulate disk and near the gap in in a ferrite recording head are presented and compared with calculated field distributions.