Abstract
A magnetic domain was observed by using an image lock-in technique for backscattered electron contrast (Type II) with a JEOL 2000FX-II 200 kV electron microscope. A thin-film head without a protective layer was excited by applying a 10 mAp-p, 100 kHz drive current. Backscattered electron were synchronously detected by using a diode detector and a look-in amplifier, and images were acquired digitally by using a LINK eXL-II system. Backscattered electrons indicated a difference in the magnetic domain configurations in the upper and lower parts of the upper pole, changing the acceleration voltage. Since the location of a pair of black and white lines in a synchronous mode shows the maximum limit of domain wall movement in one drive current period, the observed difference must have been caused by the difference in domain wall movement, that is, the difference in magnetic flux flow. Conversion of the domain configuration from the upper part to the lower part was also observed. Such conversion is possibly one of the causes of noiseafter-write.
