Magnetostriction in Fe76.5-xCu1NbxSi13.5B9

The temperature dependencies of the effective saturation magnetostriction [[Lambda].sub.s](T) of nanocrystalline [Fe.sub.76.5-x][Cu.sub.1][Nb.sub.x][Si.sub.13.5][B.sub.9] (x = 2, 3 and 5) ribbons were measured for the samples which were annealed at 480, 500, 520 and 530 [degrees] C. The nanostructure of the samples were characterized using X-ray diffraction measurements. In [Fe.sub.76.5-x][Cu.sub.1][Nb.sub.x][Si.sub.13.5][B.sub.9] (x = 2, 3 and 5) no change of sign of the effective magnetostriction was found. On the contrary [Fe.sub.73.5][Cu.sub.1][Nb.sub.3][Si.sub.16.5][B.sub.6] ribbon annealed at 530 [degrees] C, shows at elevated temperatures a compensation point in [[Lambda].sub.s](T). We suggested two mechanisms to explain this behaviour: a) for low concentration of Si in bcc-FeSi crystallites, the negative magnetostriction was not still reached; b) for higher concentration, the Curie temperature enhancement of the amorphous matrix must be considered.