Fabrication of Optically Transparent and Electrooptic Strontium Barium Niobate Ceramics

Abstract

The tetragonal tungsten bronze (TTB) type of Sr,Bal-,-Nb206 (SBN) (0.5 5 x 5 0.75) was synthesized by a mixedoxide route. Using the two-step densification process of pressureless sintering followed by oxygen HIPing, transparent ceramics were successfully fabricated. Microstructural, dielectric, optical, and electrooptic properties were investigated. All single-phase TTB-type SBN showed the characteristics of relaxor ferroelectrics. The extinction coefficients of the sample with the highest transparency were calculated from transmission spectra to be 30.4, 5.8, and 2.4 cm-I at 600, 1450, and 2000 nm, respectively. The linear electrooptic coefficients for SBN55, r33 and rI3, were 46 X lo-'' and 21 X lo-'' m/V at 633 nm, respectively. [

Spark Plasma Sintering as a Useful Technique to the Nanostructuration of Piezo‐Ferroelectric Materials

“…By way of illustration, abnormal grain growth along with crack generation and pore formation is frequently encountered in tungsten-bronze ferroelectric ceramics prepared by conventional sintering methods, which appreciably deteriorates their physical properties. [74,75] Several strategies have been used to solve such problems, including hot pressing (HP), [76,77] hot isostatic pressing (HIP), [77] dual-stage sintering [75] and the addition of sintering aids. [78] Concerning sodium and potassium niobates, until a few years ago there have been only a few reports about the piezoelectricity of NaNbO 3 , KNbO 3 and NaNbO 3 -KNbO 3 ceramics, probably because of their poor sinterability and the high volatility of the sodium and potassium components during the sintering process.…”

Investigation of nonlinear dielectric properties in Sr0.75Ba0.25Nb2O6 relaxor ferroelectric thin films

“…14 However, a sudden decrease in the a parameter was observed when compared to that obtained for bulk SBN with similar composition. 15 This structural characteristic hints the existence of the in-plane tensile strain on the thin film surface, 16 whose influence on the dielectric response of the SBN75/25 thin film will be discussed later. Figure 2 shows the temperature dependence of the linear ͑small signal͒ dielectric permittivity ͑real Ј and imaginary Љ components͒ measured at different frequencies.…”

Preparation and characteristics of seeded epitaxial (Sr,Ba)Nb2O6 optical waveguide thin films using sol-gel method

“…5 As the fraction of Sr 2+ ion content increases, more Sr 2+ ions occupy the A 2 sites and the A 1 sites become empty due to movement of Sr 2+ ions. Then the lattice of SBN having higher Sr content will be more distorted.…”

“…3 SBN is a solid solution between BaNb 2 O 6 and SrNb 2 O 6 phases with a tetragonal tungsten bronze (TTB) structure, and its physical properties vary with its composition. 5 These properties and their applications have been investigated mainly for single crystals and polycrystalline ceramics. However, the demand for thin film processing has increased due to the development of electronic and optical integrated devices.…”

“…Thus, in the sol-gel method it is very difficult to control the nucleation rate and the location of the nuclei during the crystallization of amorphous film. In addition, since the crystal and optical studies of SBN single crystal has focused on the material with mainly SBN:60 composition because of its congruent melt composition (x ‫ס‬ 0.6), 5 the characteristics of SBN thin films have also dealt with that composition. Recently, although Hirano and et al synthesized the highly c-axis-oriented SBN:50 thin films on an MgO(100) substrate by sol-gel method;…”