Structural origins of relaxor behavior in a 0.96(Bi1/2Na1/2)TiO3–0.04BaTiO3 single crystal under electric field

Abstract

Diffuse x-ray scattering intensities from a single crystal of 0.96(Bi1/2Na1/2TiO3)–0.04(BaTiO3) have been collected at room temperature with and without application of an electric field along the [100] direction. Distinct features in the diffuse scattering intensities indicate correlations on a nanometer length scale. It is shown that locally correlated planar-like structures and octahedral tilt-domains within the room temperature rhombohedral R3c phase are both electrically active and are irreversibly affected by application of an electric field of 4.3 kV/mm. The field dependence of these nanoscale structures is correlated with the relaxor behavior of the material by macroscopic permittivity measurements.

Characterization of Pb-Free KNbO3- and (Na,Bi)TiO3-Based Piezoelectric Single-Crystals Using X-ray and Neutron Diffraction

“…Kreisel et al showed from in situ high-energy X-ray diffraction experiments that application of hydrostatic pressure up to 2.8 GPa first leads to decrease in the intensity of the asymmetric diffuse scattering peaks in Na 0.5 Bi 0.5 TiO 3 single crystals, and finally to their eventual disappearance (Figure 8a) under 3.7 GPa [45]. Similar decrease in intensities of L-shaped asymmetric diffuse scattering peaks could also be observed in Na 0.5 Bi 0.5 TiO 3 single crystals under applied electric fields (Figure 8b) [78,79]. Such observations indicated that the structural differences between the matrix and the nanoscales inclusions could be irreversibly overcome by application of mechanical pressure or electric fields, ultimately leading to a phase transition in the short-range order associated with nanoscale inclusions.…”

Structure and properties of Fe-modified Na0.5Bi0.5TiO3at ambient

“…A large increase in apparent permittivity and loss with temperature is observed in the 0.5 at% Fe sample for low frequencies ( states, consistent with relaxor-type behavior. 33,34 The peak in the loss tangent vs. temperature plot is at 176 ºC for unmodified NBT and at 202 ºC for 0.5 at% Fe modified NBT (Table I).…”

Polarization Rotation and Monoclinic Distortion in Ferroelectric (Bi0.5Na0.5)TiO3–BaTiO3 Single Crystals under Electric Fields

“…Single crystals of BNT-BT have been grown and the influence on dc-bias E on the phase stability [36] and the diffuse X-ray scattering [37] have been investigated. Recently, a bifurcated polarization rotation model in BNT has been postulated by a neutron pair distribution analysis [38] and the piezoelectric response is suggested to originate from a polarization rotation.…”