Development, characterization, sintering, dielectric and optical properties of NdBa2ZrO5·5 nanocrystals

Abstract

Nanocrystalline NdBa 2 ZrO 5·5 has been successfully synthesized through a single step auto-ignition combustion route for the first time. X-ray diffraction and Fourier transform infrared spectroscopy revealed that the combustion product is phase pure and has an ordered cubic perovskite structure. The phase transitions and thermal stability of the nanopowder were investigated by differential thermal and thermogravimetric analyses. Transmission electron microscopy results indicated that the particle sizes are 20-30 nm. Selected area electron diffraction pattern has shown that as-prepared powder is polycrystalline in nature. The optical absorption spectra analysis confirmed that the material falls to the semiconducting range with a bandgap of ∼3·69 eV and therefore, could be used as transparent wide bandgap semiconductor. The relative density of the sintered sample is ∼96% at 1510 • C for 2 h. The surface morphology of the sintered pellet has been studied by scanning electron microscopy and the average grain size observed is ∼0·7 μm. Dielectric constant (ε r ) of NdBa 2 ZrO 5·5 at 5 MHz is 29·6 and loss factor (tan δ) is 4 × 10 −2 at room temperature.

Structural and Optical Properties of Sm3+ Doped B-site Ba0.5Rb0.5LaTeO6 Double Perovskites

“…The peaks of the samples at around 1422 and 1427 cm -1 might be due to vibrations of carbonate in Ba 0.5 Rb 0.5 LaTeO 6 and Ba 0.5 Rb 0.5 La 0.9 Sm 0.1 TeO 6 [26]. Another peak at around 1700 cm -1 might be due to presence of adsorbed moisture in KBr during the synthesis of the samples [27]. There is observable weak peak at 857 cm -1 which is due to external mode other than Te(Li)O 6 octahedra [28], [29].…”