MAGNETOSTRICTION IN FE(76.5-X)CU(1)NBXSI(13.5)B(9)

The temperature dependencies of the effective saturation magnetostrict ion lambda(s)(T) of nanocrystalline Fe76.5-xCu1NbxSi13.5B9 (x = 2, 3 a nd 5) ribbons were measured for the samples which were annealed at 480 , 500, 520 and 530 degrees C. The nanostructure of the samples were ch aracterized using X-ray diffraction measurements. In Fe76.5-xCu1NbxSi1 3.5B9 (x = 2, 3 and 5) no change of sign of the effective magnetostric tion was found. On the contrary Fe73.5Cu1Nb3Si16.5B6 ribbon annealed a t 530 degrees C, shows at elevated temperatures a compensation point i n lambda(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 cons idered.