Synthesis and dielectric characteristics of the layered structure Bi4−xRxTi3O12 (Rx=Pr, Nd, Gd, Dy)

FERROELECTRIC CHARACTERIZATION AND AC-CONDUCTIVITY PROPERTIES OF Bi4 − xPrxTi3O12 POLYCRYSTALS

“…3 c) we can observe the conductivity values (σ ac ) obtained for each composition. For smaller Pr content, the conductivity increases similar to what was obtained before [13]. The BIT system in pure and stoichiometric state, should behave as an insulator with very low dielectric losses.…”

“…Our studies showed that the solubility is possible in the studied range. Furthermore, to preserve charge neutrality, the doped system should generate 1/3 of oxygen vacancies as reported by Noguchi et al [11][12][13]. In this case the deficit in vacancies in the Bi-site becomes evident by changes in an internal parameter such as the TiO 6 tilting along the c-axis and the rotation angle between adjacent octahedra in the ab-plane, mainly responsible for the spontaneous polarization in BIT.…”

“…In this case the deficit in vacancies in the Bi-site becomes evident by changes in an internal parameter such as the TiO 6 tilting along the c-axis and the rotation angle between adjacent octahedra in the ab-plane, mainly responsible for the spontaneous polarization in BIT. Figure 1b shows micrographs of the dense ceramics of BIT showing the grain structure of the sintered sample, typical for BIT poycrystals [11][12][13]. Figure 2a reveals growth of particles with significantly high aspect ratio as well packed platelets with a grain size highly heterogeneous.…”

“…Kim and coworkers found that lanthanide elements greatly enhanced the rotation of the TiO 6 octahedron along the a-axis, resulting in the improvement of the ferroelectric properties [7][8][9][10]. Looking for the possibility to modify physical properties as the ferroelectric Curie point and/or the conductive characteristics of the host lattice, we have selected Pr which preserves the electroneutrality of the system besides the twelve-coordination requisite [11][12][13]. Unfortunately, the conduction mechanisms of BLSFs compounds are still unclear.…”

Dielectric–spectroscopic and AC conductivity studies in iron doped layered Na2Ti3O7 ceramics

“…The impedance spectra of Nb doped SrTiO 3 ceramic suggests that under oxidizing condition, the overall electrical behaviour is determined by two microstructural contributions [3]. Synthesis and dielectric characteristic of layered Bi 4−x R x Ti 3 O 12 has been studied by Pineda-Flores et al [4]. A series of layered perovskite with general formula A 2 Ln 2 Ti 3 O 10 (where A = Na, K, Rb and Ln = La, Nd, Gd, Dy) has been synthesized by many researchers [5,6].…”