Temperature dependence of the magnetostriction in alpha -Fe sub 100- x Si sub x and FINEMET type alloys

The temperature dependence of the saturation magnetostriction, the saturation magnetization and the coercivity of Fe sub 76.5- u Cu sub 1 Nb sub u Si sub 13.5 B sub 9 and of Fe sub 96-z Cu sub 1 Nb sub 3 Si sub y B sub w nanocrystalline alloys as well as of micro-crystalline alpha -Fe sub 100-x Si sub x (x = 12.1, 13.8 and 20) ribbons has been measured between room temperature and 500 deg C. The temperature dependence of the saturation magnetization has been analyzed in order to calculate the volume fraction of the nanocrystalline phase. From the measured temperature dependence of the saturation magnetostriction of the nanocrystalline FeCuNBSiB alloys and the micro-crystalline alpha -FeSi, we estimated the magnetostriction from the volumetrically weighted balance among Fe-Si nanocrystallites and the remaining amorphous matrix.