Synthesis, characterization, sintering and dielectric properties of nanostructured perovskite-type oxide, Ba₂GdSbO₆

摘要

Nanoparticles of barium gadolinium antimonate (Ba₂GdSbO₆), a complex perovskite-type oxide, has been synthesized using an auto ignition combustion process for the first time. The nanoparticles thus obtained have been characterized by powder X-ray diffraction, thermogravimetric analysis, differential thermal analysis, Fourier transform infrared spectroscopy and transmission electron microscopy. The XRD studies have shown that the as-prepared powder is phase pure Ba₂GdSbO₆ and has a complex cubic perovskite (A₂BB′O₆) crystalline structure with lattice constant, a = 8·449 Å. The TEM image reveals that the particle size of the as-prepared nano powder was in the range 30–60 nm. The nanocrystals of Ba₂GdSbO₆ synthesized by the combustion technique could be sintered to 96% of the theoretical density by heating at a temperature of 1560°C for a short duration of 3 h. The surface morphology of the sintered pellet has been studied by scanning electron microscope (SEM). The dielectric constant (ɛ _r) was 20 and the loss factor (tanδ) was 0·03 at 3 MHz. By the present combustion technique a phase pure nanopowder of Ba₂GdSbO₆ could be obtained by a single step process without the need of any calcination step.