Magnetoelastic coupling constant of amorphous ferromagnetic alloys - A critical study

The determination of the magnetoelastic properties in Fe-rich amorphous all oys by using resonance methods is strongly affected by the kind of measurem ent done. In this work, we compare results obtained when using the vibratin g reed method and the magnetically excited resonance one, Measurements have been performed on Fe66Co18Si1B15 amorphous ribbons with the induced anisot ropy easy axis at 60 degrees with respect to the ribbon axis. The observed differences are large in all the measured range, and especially striking in the E(H = O) / E-s initial to saturation Young's modulus ratio, After a de tailed analysis of the expressions used to derive magnetoelastic quantities from the resonant frequencies values, these discrepancies are explained by the fact that the two methods measure different quantities: dependence of the Young's modulus on the applied field (or DeltaE effect) and magnetoelas tic coupling coefficient, respectively.