Residual strain in a zinc blende Mn/sub 1-x/Mg/sub x/Te layers grown by molecular beam epitaxy

The residual strain in Mn/sub 1-x/MgTe layers grown by Molecular Beam Epitaxy (MBE) on CdTe/GaAs[001] substrates has been investigated by X-ray diffraction methods. We confirmed the existence of a tensile strain in the case of layers covered by an additional CdTe cap while in uncapped layers we found a compressive strain. The thermal expansion measurements between 300-520 K revealed an anisotropy of the inplane and out-of-plane thermal expansion coefficients. This helps to understand occurrence of the compressive strain of uncapped layers in terms of a tentative model of relaxation process in both types of layers.