Studies on structural and optical properties of rare earth copper oxides synthesized by template free hydrothermal method

The present work investigates the structural and optical properties of rare earth copper oxides (RE2CuO4; RE: Pr, Nd, Sm and Gd) and mixed metal oxides (CeO2/CuO) synthesized by template free hydrothermal method. RE2CuO4 were obtained after calcination at 700 degrees C, temperature appreciably lower than that employed in the conventional ceramic technique. The phase composition, particle size, thermal stability, morphology, elemental distribution and optical properties of the products were elucidated by various analytical techniques. X-ray diffraction patterns revealed tetragonal phase of products except for Cerium. Oval shaped particles forming agglomerates, and homogenous distribution of elements in the sample was evidenced by electron microscopy and elemental mapping. The optical band gap of the rare earth copper oxides is observed to be in the range of 0.79-1.36 eV, while CeO2/CuO shows absorption band in the UV region and a band gap of 3.24 eV. ESR analysis shows the paramagnetic behaviour of the samples.