Strain relaxation in Fe-3(Al,Si)/GaAs: An x-ray scattering study

Lattice strain of epitaxially grown single crystal Fe-3(Al,Si)/GaAs films was measured in a synchrotron x-ray scattering experiment. The Fe3Al film (2.5% lattice mismatch) was partially strained and tetragonally distorted at room temperature. As the sample was annealed to 500 degrees C, the internal strain was mostly relaxed while the tegragonal distortion was greatly reduced. We believe that the strain relaxation was caused by the interdiffusion of atoms through domain boundaries at elevated temperatures. In comparison, the Fe3Si film with much less lattice mismatch (0.17%) was completely strained up to 600 degrees C without being relaxed. (C) 1996 American Institute of Physics.