日本金属学会誌

J. Japan Inst. Metals, Vol. 50, No. 6 (1986),
pp. 523-529

119Sn Mössbauer Study on the Intermetallic Compounds in Au-Sn Alloys

Isao Tanaka1, Saburo Nasu2 and Francisco Eiichi Fuiita2

1Graduate Student, Osaka University, Toyonaka
2Department of Material Physics, Faculty of Engineering Science, Osaka University, Toyonaka

Abstract:

119Sn Mössbauer spectra of Au-Sn binary alloys with different tin concentrations from 2 to 90 at%Sn have been measured. The obtained values of the isomer shift (Δ SI) and the quadrupole splitting (Δ EQ) for four Au-Sn intermetallic compounds, ζ , AuSn, AuSn2 and AuSn4, were discussed by taking account of their crystal structures. The values of isomer shift for these compounds relative to BaSnO3 at room temperature were 2.02(3), 2.28(2) , 2.35(2) and 2.73(6), respectively. They increased almost linearly with the tin concentration except that the value of AuSn4 showed a large deviation beyond that of β -Sn. The result was well explained in terms of two characteristic features in the compounds, i.e. the number of Au near-neighbours for Sn atoms, nAu, and the specific volume of Sn atoms, VSn. The quadrupole splittings for the four compounds were 0.25(2), 0.25(2), 0.71(2) and 0.17(3), respectively. They were of the same order as that of β -Sn, except a larger splitting for AuSn2. These values well agreed with a simplified calculation of electric field gradient at a Sn site surrounded by near-neighbour Au atoms which were assumed to be point charges. The spectrum of AuSn2 was resolved into two doublets, which suggested a large difference in electronic configurations between two sorts of lattice sites of tin atoms.


(Received 1986/2/10)

Keywords:

Mössbauer spectroscopy, gold-tin alloy, intermetallic compounds, isomer shift, quadrupole splitting


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