Synthesis and some physical properties of the diluted magnetic semiconductor Cd1-xMnxO

Polycrystalline samples of cadmium-manganese mixed oxides Cd1-xMnxO were 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 crystalline structures were investigated by the Rietveld profile method based on the x-ray powder diffraction measurements. All samples were found 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 interactions between Mn2+ ions. In the paramagnetic region the Curie-Weiss law is obeyed with the linear dependence on the concentration of the effective paramagnetic temperature Theta(x) and Curie molar constant C-M(x) From the analysis of the magnetic susceptibility data, values of the 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