Evaluation of dynamic magnetic stray fields with high spatial and temporal resolution

A setup has been realized for determination of magnetic field distributions with 50‐nm spatial resolution and temporal resolution of <1 ns. For typical device configurations the system has a sensitivity of about 1 mT. Important system features are use of stroboscopic techniques; sine wave or pulsed operation of the magnetic device from 100 Hz to 60 MHz; precise determination of the distance between measuring position and head surface; and determination of the electron beam waveform by streak‐camera technique with a temporal resolution of 50 ps, even for beam currents of <1 fA. This setup has been applied to the examination of thin film magnetic heads with a 0.6‐μm gap and a track width of 26 μm.