Relaxor behaviour in BaBi4Ti4O15 ceramics fabricated using the powders obtained by mechanochemically assisted synthesis route

Abstract

Mechanochemically activated reactants were found to facilitate the synthesis of fine powders comprising 200-400 nm range crystallites of BaBi 4 Ti 4 O 15 at a significantly lower temperature (700 °C) than that of solid-state reaction route. Reactants (CaCO 3 , Bi 2 O 3 and TiO 2 ) in stoichiometric ratio were ball milled for 48 h to obtain homogeneous mixture. The evolution of the BaBi 4 Ti 4 O 15 phase was systematically followed using X-ray powder diffraction (XRD) technique. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were employed to probe its structural and microstructural details. The electron diffraction studies established the presence of correlated octahedral rotations and associated long-range polar ordering. High-resolution TEM imaging nevertheless revealed structural inhomogeneities leading to intergrowth defects. Dense BaBi 4 Ti 4 O 15 ceramics with an average grain size of 0⋅9 μm were fabricated using mechanochemically assisted synthesized powders at relatively low temperature (1000 °C). The effect of grain size on the dielectric and relaxor behaviour of BaBi 4 Ti 4 O 15 ceramics was investigated. Fine-grained ceramics (average grain size ~ 0⋅9 μm) showed higher diffusion in phase transition, lower temperature of phase transition, lower Vogel-Fulcher freezing temperature and higher activation energy for the polarization reversal than those for coarse-grained ceramics (average grain size ~ 7 μm) fabricated via the conventional solid-state reaction route.

Fortified relaxor ferroelectricity of rare earth substituted 4-layered BaBi3.9RE0.1Ti4O15 (RE = La, Pr, Nd, and Sm) Aurivillius compounds

“…The parameters obtained after fitting such as T VF , E a and are presented in the inset of Fig. 9 a–e, which are in well agreement with the previous reports 53 , 54 . The calculated activation energies are in the range between 1 to 12 meV, and relaxation time ( = ) from 10 –6 to 10 –8 s, respectively for all RE 3+ ion-substituted BBTO ceramics.…”

A graphene oxide decorated BZT–CNF composite through hybrid microwave processing: an advanced multifunctional material for superior microwave shielding applications

“…As a result of domain refinement and long-range polar ordering in magnetoelectric composite, the residual crystalline phase and reduction in grain size contribute to improved relaxor behaviour and dielectric characteristics. 57…”

“…As a result of domain renement and long-range polar ordering in magnetoelectric composite, the residual crystalline phase and reduction in grain size contribute to improved relaxor behaviour and dielectric characteristics. 57 Fig. 4(a)-(d) illustrate the relationship between relative permittivity and temperature at different frequencies.…”

Mechanochemical synthesis of nanostructured and composite oxide ceramics: From mechanisms to tailored properties

“…With the increase in Ba 2+ , the structure of the powder changed. In addition, BBT ceramic powder was synthesized using Bi 2 O 3 , CaCO 3 , and TiO 2 as raw materials by mechanical force chemistry and heat treatment at 700 • C for 5 h. 162 Mechanical activation reduces the sintering temperature of BBT ceramic powder. The size of the powder is 200-400 nm.…”