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Advances in Materials Research
  Volume 2, Number 2, June 2013, pages 77-91
DOI: http://dx.doi.org/10.12989/amr.2013.2.2.077
 


Variation in optical, dielectric and sintering behavior of nanocrystalline NdBa2NbO6
Kumpamthanath Chacko Mathai,Sukumariamma Vidya, Sam Solomon and Jijimon Kumpukattu Thomas

 
Abstract
    High quality nanoparticles of neodymium barium niobium (NdBa2NbO6) perovskites have been synthesized using an auto ignition combustion technique for the first time. The nanoparticles thus obtained have been characterized by powder X-ray diffraction, thermo gravimetric analysis, differential thermal analysis, Fourier transform infrared spectroscopy, Raman spectroscopy and transmission electron microscopy. UV- Visible absorption and photoluminescence spectra of the samples are also recorded. The structural analysis shows that the nano powder is phase pure with the average particle size of 35 nm. The band gap determined for NdBa2NbO6 is 3.9 eV which corresponds to UV-radiation for optical inter band transition with a wavelength of 370nm. The nanopowder could be sintered to 96% of the theoretical density at 1325oC for 2h. The ultrafine cuboidal nature of nanopowders with fewer degree of agglomeration improved the sinterability for compactness at relatively lower temperature and time. During the sintering process the wide band gap semiconducting behavior diminishes and the material turns to a high permittivity dielectric. The microstructure of the sintered surface was examined using scanning electron microscopy. The striking value of dielectric constant er = 43, loss factor tan s = 1.97 X 10–4 and the observed band gap value make it suitable for many dielectric devices.
 
Key Words
    nanoparticles; combustion synthesis; perovskites; neodymium; barium niobate; sintering
 
Address
Kumpamthanath Chacko Mathai : Department of Physics, St. Aloysius\'College, Edathua-689573, Kerala, India
Sukumariamma Vidya : Electronic Materials Research Laboratory, Department of Physics, Mar Ivanios College,
Thiruvananthapuram- 695 015, Kerala, India
Sam Solomon : Department of Physics, St. John\'s College, Anchal, Kollam District 691306, Kerala, India
Jijimon Kumpukattu Thomas : Electronic Materials Research Laboratory, Department of Physics, Mar Ivanios College,
Thiruvananthapuram- 695 015, Kerala, India
 

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