AN INVESTIGATION ON MAGNETOACOUSTIC EMISSION OF FERROMAGNETIC MATERIALS WITH 180-DEGREES MAGNETIC DOMAIN-WALLS

The magnetoacoustic emission (MAE) of (110)[001]-oriented 3% Si-Fe, bo th polycrystal and single crystal, and cobalt with 180-degrees magneti c domain walls only were investigated in detail. For those samples, th e magnetic domain structure was observed, and magnetization curves and hysteresis loops were measured. The MAE waveform and amplitude distri bution were plotted. The MAE activity of these samples were quite inte nse, even though the applied field was much lower than that for magnet ic saturation. The results suggest that 180-degrees magnetic domain wa ll motion does contribute to MAE. A model for the generation of the st rain waves from within the moving domain walls and the sources of MAE are discussed.