On the range of exchange interaction in Fe-type diluted magnetic semiconductors

The magnetic susceptibility of diluted magnetic semiconductors Hg1-xFexSe, Zn1-xFexSe and Zn1-xFexS has been calculated within a crystal field model applying the extended nearest-neighbour pair approximation. The results are compared with available experimental data. Taking the long-range antiferromagnetic exchange interaction between Fe2+ ions in the form J(R) = J(NN)/R-n, good agreement between theory and experiment is obtained for Hg1-xFexSe with 11 K less than or equal to \J(NN)\ less than or equal to 15 K and n = 5, and for Zn1-xFexSe with J(NN) = -22 K and n = 6.8. We find that the crystal field model gives a good description of the magnetic susceptibility of Zn1-xFexS using only the nearest-neighbour exchange interaction, J(NN) = -37 K.