Atomic disorder in AlFeNiV multi-component alloys and its effect on the magnetic properties

Abstract

Order-disorder transition presents a pivotal and intricate challenge in materials science. In this work, AlFeNiV multi-component alloys were prepared with distinct heat treatment processes (named as-cast, spin, and anneal) to investigate the order-disorder transitions, local lattice distortion and their effect on the magnetic characteristics. Phase structure analysis demonstrates that the AlFeNiV alloy with a Heusler structure undergoes a distinctive phase transition from L2₁ to B2 structure at around 1000 °C. Local lattice structure analysis reveals that all the three samples exhibit a tensile stress state, with the annealed sample exhibiting a lower local lattice distortion. Quantitative atomic occupancy analysis indicates that the spin sample has a lower degree of ordering and exhibits comparatively stronger magnetic properties, which are attributed to the formation of antisite defects between the 4b and 8c sites. This work provides a scientific understanding for the design of advanced alloys with predicted properties by using defect engineering.