Structure and Spin-Glass Magnetism of the Fe 1.5 Ni 1.5 Ga 4 Metallic Alloy

High Resolution Image Download MS PowerPoint Slide The Ga-rich region of the Fe–Ni–Ga ternary system was investigated, by exploring a line of compositions Fe x Ni 3– x Ga 4, with 0.5 ≤ x ≤ 2.5. The single-phase cubic material was found only at the composition Fe 1.5 Ni 1.5 Ga 4 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 Fe x Ni y Ga z around the central composition Fe 1.5 Ni 1.5 Ga 4 . The structural model was constructed based on the structure of the binary Ni 3 Ga 4 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 48 g Wyckoff site. The possibility of a symmetry-reduced chiral structural model I 4 1 32 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 Fe 1.5 Ni 1.5 Ga 4 phase has revealed that the material forms a spin glass phase below the spin freezing temperature T f ≈ 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.