Profiling of micromagnetic stray fields in front of magnetic recording media and heads by means of a SEM

A modified scanning electron microscope (SEM) can be used for profiling micromagnetic stray field components in front of magnetic recordings and heads. The physical principle is the deflexion of the primary electron beam by the Lorentz force, if the beam passes the field region. This deflexion is monitored by a two-dimensional electron detector and quantified by a digital video frame memory in connection with a host process computer. Amplitude and direction of the deflexion are directly related to those components of the magnetic field vector which are normal to the electron beam direction. High spatial resolution and sensitivity lead to a high usefulness of the measurement system. The two-dimensional stray field distribution profile in front of a digital magnetic recording and a "flying head" are imaged.