Time-resolved measurement of micro-magnetic field by stroboscopic electron beam tomography

Stroboscopic electron-beam tomography has been achieved for time-resolved measurement of the magnetic recording thin-film head. The transition characteristics of magnetic field distributions were compared; the driving current was found to have a temporal resolution of 1 ns. Both the driving current waveforms and the magnetic field distributions are measured by a pulsed electron beam with the same timing pulse gate. This measurement was successfully applied to Ni-Fe and CoTaZr amorphous thin-film disk heads. It was found that the magnetic field distribution change with time is not uniform and that the peak field is a few nanoseconds behind the driving current for Ni-Fe heads. The frequency characteristics of these heads correspond for the magnetic field delay to the driving current. The frequency characteristics of the head whose magnetic field delay is longer are inferior to those of the head whose magnetic field delay is shorter