Finemet合金核外电子间相互作用的正电子湮没多普勒展宽谱研究

The extranuclear electron interaction of Finemet alloy studied by using Doppler broadening spectrum of positron annihilation

摘要:

采用双高纯锗探头符合的正电子湮没技术测量了Finemet合金各组元以及在350℃、380℃和400℃下退火(10分钟)的Finemet非晶薄带的多普勒展宽谱，对Finemet合金热处理过程中元素核外电子间的相互作用进行了研究。结果表明，Finemet合金淬火态商谱（参照样品为硅）的谱峰比纯金属元素Fe、Cu、Nb的谱峰要低，Fe和Nb之间存在着3d-4d轨道键合作用。随着退火温度的升高，Fe原子的3d电子与Nb原子的4d电子之间的轨道键合作用增强，商谱的谱峰降低，Cu原子易在表面富集，而Nb原子则在非晶薄带中富Fe区域里重新分布。

Abstract:

In this paper, we measured the Doppler broadening spectrum for positron annihilation of Finemet alloy elements and Finemet amorphous ribbons which annealed at 350℃, 380℃ and 400℃ respectively (10mins) by using two HP-Ge detector coincidence technique, in order to investigate the extranuclear electron interaction during annealing process. Results present that the peak of the ratio curve (the reference sample is Si) for asquenched Finemet ribbon is relatively low compared with those pure alloy elements Nb, Fe and Cu, because there exists a bonding between 3d orbit electrons in Fe atoms and 4d orbit electrons in Nb atoms. With the annealing temperature increasing, the peaks of ratio curves decreased and indicated that the bonding became more intensified. The strengthened extranuclear electron interaction caused that the Cu atoms tend to enrich in the surface and the Nb atoms would redistribute to the iron - rich area of amorphous ribbon.