Local detection of magneto-surface-acoustic-wave in highly magnetostrictive amorphous film by light-probing technique

we present an investigation on local properties of magneto-surface-acoustic-waves (MSAWs) propagating on Fe-Co-B amorphous sputtered films supported on soft glass substrates. The local detection of MSAW was performed by means of a light-probing technique based on the principle of Raman-Nath diffraction. The mode of MSAW in the elements was confirmed to be Rayleigh(P+SV)-type and the amplitude of MSAW was subjected to large change from place to place by applying a small field. The attenuation constant of MSAW also varied depending strongly, not only on the field strength, but also on the direction of the field relative to the direction of MSAW propagation. Theoretical analysis explains the experimental results very well in terms of the change of micro-eddy current loss in the conductive magnetic film, which reflects the change in the degree of magnetoelastic coupling in the film with external magnetic field.