Search

Non-stoichiometric lead free polycrystalline Sr0.8Sn0.2Bi1.75Sm0.25Nb2O9 (SSBSN) ferroelectric ceramics were synthesized through conventional solid step route method by incorporating ball milling and microwave sintering method. X-ray diffraction along with the Rietveld refinement technique confirms the single-phase orthorhombic structure with A21 crystal symmetry. Additionally, the short-range ordering was confirmed by Raman spectroscopy. Doping induced crystallite size and strain were further calculated from the Williamson-Hall plot, which comes around 150 nm and 1.48 × 10–3 respectively. A plate like morphology with an average grain size of 0.41 μm was confirmed by scanning electron microscopy (SEM). A diffuse type ferroelectric to paraelectric phase transition was recorded at 395 °C, mostly arising due to structural heterogeneity at the inter-ferroelectric phase boundary. The temperature and frequency-dependent dielectric measurement of SSBSN ceramic reveal a Maxwell–Wagner relaxation, with prominent dielectric loss in a low frequency regime perhaps due to the generation of leakage current in the SSBSN system. Frequency dependent ac conductivity indicates the polaron assisted hopping mechanism in SSBSN, which further obeys Jonscher’s formulation. The intra and intergranular contributions to impedance in SSBSN ceramics were probed by the complex impedance spectroscopy (CIS) technique. A non-Debye type relaxation mechanism in SSBSN ceramics was indicated by the Cole–Cole plot, whereas the conduction mechanism and transport properties were briefly studied using modulus spectroscopy. [ABSTRACT FROM AUTHOR]

SrBi 2 Nb2O 9 belongs to the class of Aurivillius layered ferroelectric oxide materials and this article offers a suitable method for understanding the structural and electrical properties of this class material for industrial application. With this aim we have synthesized LaFeO 3 (LFO) doped Sr 0.8 Sn 0.2 Bi 2 Nb 2 O 9 (SBN) novel ceramic by solid state route using ball milling in an ethanol medium for 20 h with 200 rpm, followed by single-step microwave sintering. For better phase formation, the obtained powders are compressed into cylindrical pellets and fired at 1000 °C for 5 h. The sample was critically analyzed using powder X-ray diffraction data confirming the distorted perovskite structure. The dielectric properties were studied in a frequency range of 10 Hz to 2 MHz at different temperatures revealing many exciting results. Further analyzing the impedance spectroscopy gives an idea about the contribution of different electrically dynamic regions in different conduction processes. • Synthesized lead-free ferroelectric LSBN composition using solid-state route method, which is very challenging to execute. • The Uniform deformation model (UDM) has been used to study the effect of strain and crystallite size on peak broadening. • Impedance spectroscopy reveals that the relaxation mechanism in LSBN composition is a thermally governed process. • Contribution of capacitive elements to the total impedance spectra has also been investigated by employing modulus spectroscopy. [ABSTRACT FROM AUTHOR]