ELENA-ADRIANA PERIANU, IOANA AURELIA GORODEA, FELICIA GHEORGHIU, ANDREI VICTOR SANDU, ADELINA CARMEN IANCULESCU, ION SANDU, ALEXANDRA RALUCA IORDAN, MIRCEA NICOLAE PALAMARU PREPARATION AND DIELECTRIC SPECTROSCOPY CHARACTERIZATION OF A2MNMOO6 (A = CA, SR AND BA) DOUBLE PEROVSKITES
The aim of this work is to study the behavior of the perovskite-type complex oxides A2MnMoO6 obtained by the citrate combustion synthesis method. We have prepared our samples of nanosized perovskite-type complex oxides A2MnMoO6 (A = Ca, Sr and Ba) by citrate combustion method. The starting materials were CaCO3, SrCO3, BaCO3 (treated with HNO3 to form active nitrates), (NH4)6Mo7O24 · 4H2O, Mn powder and citric acid in stoichiometric ratio. The precursors were presintered and sintered at different temperatures. The obtained powders were firstly characterised by infrared spectrophotometry. The infrared spectra have revealed several novel aspects of the structure. The position of bands indicates that all nanosized materials are polymetalic oxides exhibiting perovskite-type structure. The complex impedance properties have also been determined and they are discussed in relationship with the composition of the samples.
Keywords: double perovskites, sol-gel preparation, X-ray diffraction, SEM, Electrical properties