Sol-gel synthesis of fine Gd2CuO4 particles: Influence of synthesis variables

Fine particles of Gd2CuO4 were prepared by a sol-gel reaction of an aqueous solution of metal nitrates in the presence of urea, which leads to high-homogeneity polycrystalline powders of Gd2CuO4. We have studied the synthesis conditions, demonstrating the existence of a relationship between the calcination temperature and the heating time needed to attain the pure phase, Gd2CuO4 was obtained at temperatures of the order of 650 degrees C, lower than temperatures employed in the conventional ceramic technique. The influence of the [urea]/[salts] ratio and an excess of Cu(II) in the starting solution was also studied and discussed, X-ray powder diffraction, inductively coupled plasma atomic emission spectroscopy (ICPAES), photon correlation spectroscopy (PCS), and transmission electron microscopy (TEM) were used to characterize the Gd2CuO4 samples obtained.