Hyperfine Interact (2016) 237:8 DOI 10.1007/s10751-016-1221-9 The hyperfine properties of iron-gallium alloys M. Elzain 1 · A. Gismelseed 1 · A. Al-Rawas 1 · A. Yousif 1 · H. Widatallah 1 · Maya Al-Azri 1 · M. Al-Barwani 2 © Springer International Publishing Switzerland 2016 Abstract The hyperfine properties at Fe site in iron-gallium alloy are calculated using the full-potential linear-augmented-plane-waves method. We have calculated the Fermi contact field (B hf ) and isomer shift (δ) at the Fe site versus the number of neighbouring Ga atoms. We found that B hf decrease whereas δ increases with increasing number of neighbouring G atom. In addition we have calculated the hyperfine properties of FeGa system with DO 3 structure, where various distributions of 4 the Ga atoms in the conventional unit cell are considered (including the regular DO 3 structure). We found that the DO 3 structure has the lowest energy as compared to the other configurations. The two distinct A and D sites of the ordered DO 3 conventional unit cell have two distinct values for B hf and δ. On changing the atomic arrangement of the Ga atoms within the conventional unit cell, the configuration of the A site is maintained whereas that of the D site becomes imperfect. The contact magnetic hyperfine fields of the D-like sites in the imperfect structures are lower than that of the DO 3 D site. Keywords Isomer shift · Hyperfine field · Phases 1 Introduction The iron-gallium alloys possess large magnetostriction that promises potential applications as sensors and actuators [1]. The Fe-Ga alloys supersede other materials through their low This article is part of the Topical Collection on Proceedings of the International Conference on the Applications of the M ¨ ossbauer Effect (ICAME 2015), Hamburg, Germany, 13–18 September 2015  M. Elzain elzain@squ.edu.om 1 Department of Physics, Sultan Qaboos University, Box 36, Al Khod 123, Oman 2 NYU Abu Dhabi, Box 129188, Abu Dhabi, United Arab Emirates