SYNTHESIS AND SOME PHYSICAL-PROPERTIES OF THE DILUTED MAGNETIC SEMICONDUCTOR CD1-XMNXO

Polycrystalline samples of cadmium-manganese mixed oxides Cd1-xMnxO we re synthesized by ceramic technology in a wide range of concentrations x (0.05 less than or equal to x less than or equal to 0.90). Their cr ystalline structures were investigated by the Rietveld profile method based on the x-ray powder diffraction measurements. All samples were f ound to be of sodium chloride structure type with lattice constants a( x) slightly deviating from the Vegard law. Thermogravimetric analysis shows that samples are unstable above 500 K owing to the absorption of oxygen by MnO. Magnetic susceptibility chi(x, T) measurements made by the Faraday method indicated the presence of antiferromagnetic intera ctions between Mn2+ ions. In the paramagnetic region the Curie-Weiss l aw is obeyed with the linear dependence on the concentration of the ef fective paramagnetic temperature Theta(x) and Curie molar constant C-M (x) From the analysis of the magnetic susceptibility data, values of t he spin and the nearest-neighbour exchange integral were found to be S = 2.6 +/- 0.1 and J(1)/k(B) = 11 +/- 1 K, respectively.