MAGNETOREFLECTANCE AND MAGNETIZATION OF THE CO-BASED WURTZITE-STRUCTURE DILUTED MAGNETIC SEMICONDUCTOR CD1-XCOXSE

Magnetoreflectance measurements of excitonic interband transitions in the wurtzite-structure compound Cd1-xCoxSe with various directions of applied magnetic field combined with magnetization measurements, allowed us to determine the ion-carrier exchange parameters for the conduction and valence bands (N0-alpha=25+/-10 meV, N0-beta=-1883+/-30 meV), without making any assumption concerning the band parameters. The magnitude of these exchange parameters, compared with the values previously obtained for Cd1-xFexSe and Cd1-xMnxSe, indicates a small variation of the conduction-band exchange parameter, but an important enhancement of the valence-band exchange parameter. This large variation of the hybridization-induced exchange is explained within a generalized Schrieffer-Wolff formula.