Micro-structural investigations and paramagnetic susceptibilities of zinc oxide, europium oxide and their nanocomposite

Nanoparticles of zinc oxide (ZnO), europium oxide (Eu₂O₃) and their nanocomposite system {(ZnO)_0.55(Eu₂O₃)_0.45} have been prepared by pyrophoric reaction and chemical co-precipitation methods. The precursor materials used for the synthesis were Zn(NO₃)₂·6H₂O and bulk Eu₂O₃. For nanocrystallization, the as-prepared samples were annealed at 500 and 600 °C for 6 h. The X-ray diffractograms (XRD) confirmed the formation of desired phases of the nanoparticles of ZnO, Eu₂O₃ and nanocomposite of {(ZnO)_0.55 (Eu₂O₃)_0.45}. Particle sizes of all the samples have been estimated from the width of the XRD peaks using the Debye-Scherrer equation. Particle sizes, crystallographic phases, etc. extracted from the high resolution transmission electron microscopy of a few selected samples are in agreement with those obtained from the XRD. Field emission scanning electron microscopy showed that ZnO nanoparticles are more-or-less spherical in shape. Average magnetic susceptibilities of all the annealed samples measured in the temperature range of 300-14 K indicate that all the samples including the zinc oxide, which is normally diamagnetic in the bulk state, are paramagnetic and the data are tried to analyze by the Curie-Weiss law. Photo-luminescence data recorded at room temperature of all the samples indicate that the optical property of the ZnO nanoparticles are not affected by Eu₂O₃ nanoparticles in the nanocomposite system though its bulk magnetization is substantially enhanced by incorporating the Eu₂O₃ nanoparticles.