Study On Preparation, Structure And Properties Of Ba_1-x-yCa_xSr_yTiO₃Ferroelectric Ceramics

Ba1-x-yCaxSryTi03ceramics (x=0.0-0.25,y=0.0-0.3) were prepared using the sol-gel technique reaction method in this paper. different components of ceramic microstructure and surface morphology were analyzed using X-ray diffraction and scanning electronic microscope. Ba1-x-yCaxSryTiO3ceramics electric hysteresis loop, the dielectric properties, dielectric tunability, quality factor, the displacement of piezoelectric response, piezoelectric, reverse current curve is analyzed by TF Analyzer2000. Their structural and dielectric properties were characterized. for ceramic samples under different sintering temperature of dielectric constant and piezoelectric coefficient, dielectric tunability and quality factor are discussed. Ba1-x-yCaxSryTiO3ceramic the residual polarization and coercive field are analyzed under different electric field.Near the solubility limit, the polarization mechanism, such as domain wall motions, defects, and phase boundary polarization was attributed to the enhancement in the dielectric properties.For the BSCT series ceramics with a10-20mol%Sr content,the samples’ dielectric tunability had quite a large value of reach76.2%and90.4%, even though the remnant polarization and electrostrictive strain decreased with an increase in the Ca content. The tunability values increased with an increase in the Sr content,because the tunability in the soluble area was higher than that in the diphasic region, owing to the existence of microregions and the domain wall motion during the switching of polarizationSuch materials will be useful for various electromechanical applications. In ABO3perovskite structure Ba ions replacement of by Ca ion and Sr ions. the tunability was suppressed with increasing Ca content.It has been found that Sr doping of the BCT ceramics causes a drastic decrease of the Curie temperature, just like Sr doping of pure BaTiO3ceramics, demonstrating a cell volume effect. The enhancement of their polarization was by the increase of the lattice parameter c/a ratio due to the lattice distortion and strain developed in the ceramics. The materials with high tunability do not always exhibit high permittivity.The dielectric constant, tanδ and tunability decrease with increasing the amount of Ca, and the value of FOM increases.