CARRIER-DENSITY DEPENDENCE OF THE EXCHANGE COUPLING BETWEEN MAGNETIC IONS AND CONDUCTION BAND ELECTRONS IN HEAVILY n-TYPE Zn(1-x)MnxSe AND OPTICALLY PUMPED Cd(1-x)MnxTe

Abstract

We report on the analysis of the influence of carrier concentration on the exchange coupling between conduction band electrons and Mn d-electrons in diluted magnetic semiconductors. For this analysis we employed (i) electronic spin-flip Raman spectroscopy on heavily n-doped ( Zn , Mn ) Se , (ii) time-resolved Faraday rotation on optically pumped ( Cd , Mn ) Te . With increasing carrier density, a reduction of the exchange energy N0α up to 30 % is observed. It is explained by a weakening of the ferromagnetic character of the coupling of conducton-band electrons to the Mn d-electrons by an admixture of an antiferromagnetic (p-d) coupling contribution to the ferromagnetic (s-d) one for q ≠ 0.