Abstract:
Solid-state synthesis in Ni/Fe/MgO(001) bilayer epitaxial thin films has been studied experimentally. The phase sequence Fe/Ni→(∼350°C)Ni3Fe→(∼400°C)NiFe→(∼ 550°C)γpar is formed as the annealing temperature increases. The crystal structure in the invar region consists of epitaxially intergrown single-crystal blocks consisting of the paramagnetic γpar and ferromagnetic NiFe phases, which satisfy the orientation relationship [100](001)NiFe ∥ [100](001) γpar. It has been shown that the nucleation temperatures of the Ni3Fe, NiFe, and γpar phases coincide with the temperatures of solid-state transformations in the Ni-Fe system.