Controlled growth and magnetic properties of chemically synthesized Ni–Mn(-Ga) alloy films

The crystallographic evolution of chemical synthesized Ni- 100- x - y Mn x -Ga y ( x = 35-75, y = 0-1) alloy films has been investigated to clarify their growth mechanism from the precursor upon annealing. The use of buffering agent is found to promote a highly (001)-oriented LDH precursor film with compositional homogeneity. Subsequent annealing of LDH films at T a = 1073 K in air yields their transformation to the spinel oxide, and eventually to the FCC alloy via heat treatment at T a = 1073 K in N 2 : H 2 . Varying the Mn composition x yields an increase in the LF from 0.15 to 0.60 and in the saturation magnetization from 106 to 139 emu cm⁻³. Structural analysis of the samples has a crystallographic orientation relationship between the (111) spinel and (111) FCC films through topotactic transformation pathway. The controlled growth of films demonstrated one of the most promising bottom-up approaches for fabricating crystallographyically highly oriented alloy films.