ARRANGEMENT FOR THE INVESTIGATION OF DOMAIN BEHAVIOR UNDER LOW-FREQUENCY MAGNETIC-FIELDS

The magnetic energy of a material as function of the magnetising field has many minima, each of which corresponds to an individual domain ar rangement. The number of minima depends on the magnetic anisotropy and the frequency of the magnetic field. By changing the magnetic field, the domain picture varies, and these changes characterise the dynamic properties of the material. Soft magnetic materials with strong magnet ic anisotropy have only a few minima and in such materials there will be only a few different domain arrangements during the change in the m agnetic field. The setup for the domain investigations consists of an Intel 8096 microcontroller, which controls a Jeol 840 scanning electro n microscope synchronised with the magnetic field. The stroboscopic me thod of taking pictures works up to 2000 Hz and the domain images are averaged to improve the signal-to-noise ratio.