Structure and magnetic properties of epitaxial ordered FePd (001) thin films

Equiatomic FePd (001) thin films have been deposited by Molecular Beam Epitaxy on a Pd (001) surface. We show that the degree of chemical order in the epitaxial layer is highly dependant on the temperature of deposition thus leading to a drastic change in the magnetic properties. At 25 degrees C, while the RHEED oscillations reveal a layer by layer growth, the structural study demonstrates that the disordered phase has grown. In that case, the easy magnetization axis lies in the plane of the layer. At 350 degrees C, the RHEED oscillations show that the growth proceeds bilayer by bilayer. We find that the tetragonal L1(0) ordered phase is stabilized with its 4-fold symmetry axis along the growth direction and this results in a perpendicularly magnetized thin film. The Transmission Electron Microscopy study reveals the presence of twins and antiphase boundaries in the ordered film.