Extranuclear Electron Interaction of Finemet Alloy Studied by Using Doppler Broadening Spectrum of Positron Annihilation

Abstract:

The ratio curves of Finemet alloy elements and Finemet amorphous ribbons(annealed at 350 ℃,380 ℃ and 400 ℃ for 10min respectively)were measured with the Doppler broadening spectrum of positron annihilation which adopted two HPGe detector coincidence technique to investigate the extranuclear electron interaction during annealing process.Results show that the peaks of asquenched Finemet ribbons is relatively low after a comparison with the ratio curves of pure elements Nb,Fe and Cu.There exists a bonding between 3d orbit electrons in Fe atoms and 4d orbit electrons in Nb atoms.The bonding become more strengthened with the increment of annealing temperature,which leads the peaks of ratio curves to decrease.Meanwhile,the Cu atoms tend to be enriched in the surface and the Nb atoms redistribute to the amorphous layer of ribbon where the Fe atoms are rich.