Materials Research Bulletin, Vol.43, No.2, 312-319, 2008
Optical, magnetic and electronic properties of Ln(2)O(2)Te (Ln = La, Sm and Gd)
The synthesis, the optical and magnetic properties and the electronic structure of the rare-earth oxytellurides of formula Ln(2)O(2) Te (Ln = La, Sm and Gd) are reported. The magnetic measurements show that La2O2Te exhibit a diamagnetic behavior. The value of the magnetization M of Gd2TeO2 at our highest available field (50 kOe) is about 5.5 mu(B), well below the expected value for two independent Gd ions (2gJ = 14 mu(B)) confirming the antiferromagnetic character of this compound. The magnetic properties of Sm2TeO2 reveal that Sm is in its 3+ oxidation state with a large Van Vleck contribution. The electronic structure calculations, studied by means of a first principles DFT approach, are consistent with the optical measurements and suggest an indirect band gap semiconductor behavior. (c) 2007 Elsevier Ltd. All rights reserved.
Keywords:chalcogenides;inorganic compounds;chemical synthesis;optical properties;electronic structure