Properties of epitaxial films of γ-Fe and γ-Mn

LEED (low-energy electron diffraction) analyses of thick (10 to 20 layers) epitaxial films of γ-Fe on Cu{001} and of γ-Mn on Pd{001} allow the determination of the bulk interlayer spacing in the direction perpendicular to the plane of the film. Analysis of the strain imposed by the substrate on the epitaxial films permits identification of the structure type and of the lattice parameters of the corresponding equilibrium (unstrained) metastable phase grown. An error in a previous strain analysis is corrected, and the strain analysis now indicates that the films are elastically soft. Comparison of the results of the strain analysis with those of both earlier X-ray measurements on small alloy precipitates and total-energy band-theory calculations leads to the conclusion that the films of γ-Mn on Pd{001} are in the tetragonally distorted antiferromagnetic state, while the films of γ-Fe on Cu{001} are probably in the cubic ferromagnetic state, although a slightly tetragonally distorted antiferromagnetic state cannot be ruled out. © 1989.