The Ga-rich region of the Fe-Ni-Ga ternary system was investigated, by exploring a line of compositions FexNi3-xGa4, with 0.5 ≤ x ≤ 2.5. The single-phase cubic material was found only at the composition Fe1.5Ni1.5Ga4 and its immediate vicinity, representing a new phase in the Fe-Ni-Ga diagram. The homogeneity range of this phase was estimated by additionally exploring a set of compositions FexNiyGaz around the central composition Fe1.5Ni1.5Ga4. The structural model was constructed based on the structure of the binary Ni3Ga4 parent phase, which crystallizes in the cubic Ia 3̅ d space group. We have considered that by substituting Fe for Ni, the Ia 3̅ d structure is preserved, with the Fe and Ni being statistically distributed at their 48g Wyckoff site. The possibility of a symmetry-reduced chiral structural model I4132 driven by chemical ordering of Fe and Ni cannot be entirely ruled out on the basis of the crystallographic study. The magnetic study of the Fe1.5Ni1.5Ga4 phase has revealed that the material forms a spin glass phase below the spin freezing temperature Tf ≈ 9 K. Since the spin glass ordering of the Fe and Ni magnetic moments is compatible with their random distribution, the magnetic study supports the disordered cubic Ia 3̅ d model.
Buxi et al. (Fri,) studied this question.