Dielectric function of the ferromagnetic semiconductor CdMnCrTe studied by using spectroscopic ellipsometry

We describe the pseudo-dielectric function of Cd1-x-y Mn (x) Cr (y) Te ferromagnetic semiconductor alloys by using spectroscopic ellipsometry in the 1.0 similar to 6.0 eV spectral range at room temperature. The ellipsometry data include structures that can be attributed to the effects of Cr concentration on the E (0), E (1), E (1) + Delta(1), and E (2) critical points. Critical-point (CP) parameters were obtained by fitting standard critical point (SCP) model line shapes to the numerically-calculated second- energy derivatives of epsilon(omega) = epsilon (1)(omega) + i epsilon (2)(omega). The E (0), E (1), E (1) + Delta(1), and E (2) energies decreased with Cr content y; this phenomenon is related to the hybridization of the valence and the conduction bands in CdTe with the 3d states of Mn and Cr.