The relationship between the defect structure and Li vacancy ordering in  phase (Fd3m) samples, with Li contents of between 44 and 54at%, was studied. On the basis of the dependence of the lattice parameter and density upon the Li content, a model was proposed in which the defect structure in the  phase comprised 2 types of defect. These were Li vacancies, VLi, and Li antisites, LiGa. It was found that VLi was the predominant defect in Li-deficient compositions, while LiGa was the predominant defect in samples with a Li excess. It was suggested that the strain energy that arose from the point defects was released by forming a VLi-LiGa complex. Ordering of the Li vacancies, which introduced an anomalous electrical resistivity at around 230K, was obstructed by the formation of the complex defect.

K.Kuriyama, H.Hamanaka, S.Kaidou, M.Yahagi: Physical Review B, 1996, 54[9], 6015-8