Crystallographic and magnetic properties of thin films of iron epitaxially grown on F.C.C. substrates

Abstract

Experiments have been carried out in which iron films were epitaxially grown by vacuum evaporation onto (100) surfaces of f.c.c. metals. When a gold substrate is used (a ₀ = 4·07 Å) the orientation relation between the two films is: The orientation relation between an iron film and nickel substrate (a ₀ = 3·52 Å) is: Using substrates with lattice parameters between those of gold and nickel, varying percentages of the two types of orientation are seen to be present in electron diffraction patterns. The iron films produced are fine grained and the orientation of each grain is one or the other of the two types described. Models for the two types of crystal growth are developed. The films have interesting magnetic properties since both types of orientation have cubic anisotropy but there is an angle of 45° between the easy directions in the two cases. By using formulae for the anisotropy energy of the two types of crystal the percentages necessary to produce an isotropic film are calculated. The domain structure of the films was studied by Lorentz electron microscopy and experimental evidence supporting the theoretical predictions is described.