Influence of kinetics on the phase formation in epitaxial Fe–Pd films

Highly strained epitaxial growth is possible when using materials with an inherent structural instability. Here, we investigate the critical thickness and the relaxation mechanism of Fe70Pd30 magnetic shape memory alloy films by diffraction methods and transmission electron microscopy. By comparing films deposited with different rates we identify accumulation of defects as the only relaxation path accessible at room temperature. Our analysis of strained growth reveals the importance of relaxation kinetics in addition to the common thermodynamic arguments.