Synthesis, characterization, sintering and dielectric properties of nanostructured perovskite-type oxide, Ba_2GdSbO_6

摘要

Nanoparticles of barium gadolinium antimonate (Ba_2GdSbO_6), 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 Ba_2GdSbO_6 and has a complex cubic perovskite (A_2BB'O_6) crystalline structure with lattice constant, a = 8.449 A. The TEM image reveals that the particle size of the as-prepared nano powder was in the range 30-60 nm. The nanoerystals of Ba_2GdSbO_6 synthesized by the combustion technique could be sintered to 96 percent of the theoretical density by heating at a temperature of 1560 deg 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 (epsilon_r) was 20 and the loss factor (tan delta was 0.03 at 3 MHz. By the present combustion technique a phase pure nanopowder of Ba_2GdSbO_6 could be obtained by a single step process without the need of any calcination step.