0000000000194652
AUTHOR
G. Klimkowski
Uniaxial Pressure Effect on Dielectric Properties of 0.7Na0. 5Bi0.5TiO3‐0.3SrTiO3Ceramics
The 0.7Na0.5Bi0.5TiO3-0.3SrTiO3 ceramics were prepared by a solid-state mixed-oxide technique at 1180°C. X-ray diffraction and Raman spectroscopy studies revealed that the obtained samples possess perovskite structure. The behaviour of the electric permittivity (ɛ) and polarization of these ceramics as a function of uniaxial pressure (0 – 1000 bar) were investigated. Applying pressure shifts and decrease of maximum value of ɛ, a diffuseness of the permittivity characteristics, decrease of the thermal hysteresis and change of the polarization. We discuss our results based on elastic changes in inter-ionic distances in the crystal structure and nanoregions switching processes by pressure. The…
SrTiO3and Pr Effects on Structural, Dielectric and Ferroelectric Properties of Na0.5Bi0.5TiO3Ceramic
[(Na0.5Bi0.5TiO3)0.7Sr0.3]1-xPrxTiO3(NBTS30P) (0 ≤ x ≤ 0.025) ceramics were prepared by solid-state synthesis process. Their crystal structure, microstructure dielectric and ferroelectric properties were studied. XRD data show that all of the ceramics possess a single perovskite phase. SEM results confirm that the ceramics are well sintered and exhibit relative densities higher than 97%. The results also reveal that the microstructure of the different compositions do not show a significant variation. The praseodymium (Pr) substitution to NBTS30 results in a change of crystal structure from cubic to tetragonal at x = 0.025. At the same time, electric permittivity decreases, the maximum is br…
Influence of Compressive Stress on Dielectric and Ferroelectric Properties of the Na0. 5K0.5NbO3, Na0.5K0.5(Nb0.94Sb0.06)O3and Na0.5K0.5(Nb0.94Sb0.06)O3+0.5mol%MnO2Ceramics
Good quality lead-free ceramics of Na0.5K0.5NbO3, Na0.5K0.5(Nb0.94Sb0.06)O3 and Na0.5K0.5(Nb0.94Sb0.06)O3 +0.5mol%MnO2 have been produced by a solid phase hot pressing sintering process at 1120–1145°C. The dependence of dielectric and ferroelectric properties on the uniaxial pressure (0–3000 bar) of the these samples was investigated, revealing a significant influence of the external stress on their properties. This includes a shift of the phase transition, a diffuseness of the permittivity characteristics, a change of the dielectric dispersion and a decrease of the polarization. We discuss our results based on hardening of the soft-mode and domain switching processes under applying of pres…
Influence of Compressive Stress on Dielectric and Ferroelectric Properties of the(Na0.5Bi0.5)0.7Sr0.3TiO3Ceramics
Good quality lead-free ceramics of (Na0.5Bi0.5)0.7Sr0.3TiO3(NBTS30) have been produced by a solid phase sintering process. The dependence of dielectric and ferroelectric properties on the unaxial pressure (0–1200 bar) were investigated. A shift and decrease of maximum value of e, decrease of the thermal hysteresis and coercive field and increase of polarization with increasing pressure were observed. The results were discussed in terms of an elastic changes in inter-ionic distances in a crystal structure and switching nanoregions under the action of pressure. The NBTS30 ceramic is expected to be a new promising candidate for lead-free electronic material.
The Electrical Properties of Ba1-ySryZrxTi1-xO3Solid Solution
A lead-free solid solution Ba0.80Sr0.20Ti0.75Zr0.25O3 was prepared by a conventional technology. The structure and morphology of investgated samples were characterised by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The studies of electric conductivity were performed depending on temperature and frequency of electric measuring field. The activation energy was calculated from the Arrhenius plots.
Influence of Compressive Stress on Dielectric and Ferroelectric Properties of the 0.9PbSc0.5Nb0.5O3-0.1PbLu0.5Nb0.5O3Ceramics
0.9PbSc0.5Nb0.5O3-0.1PbLu0.5Nb0.5O3ceramics were prepared by a solid-state mixed-oxide technique. The phase formation and microstructure were studied using X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. The influences of compressive stress (0 – 1500 bar) applied parallel to the electric field on the dielectric and ferroelectric properties of these ceramics were investigated. The results showed that the compressive stress had pronounced effects on these properties. With increasing pressure, the electric permittivity maximum decreases and shifts to higher temperature, thermal hysteresis, dielectric dispersion and polarization decrease. The obtained results were …
Sb Effect on Structural, Dielectric, and Ferroelectric Properties of Na0.5K0.5NbO3Ceramics
Lead-free Na0.5K0.5(Nb1-xSbx)O3 (0<x<0.05) ceramics were fabricated by the solid-state reaction method and materials with more than 95% densification were obtained. A microstructure study confirms that the ceramics are well sintered. All compositions show complete perovskite solid solutions. Structural, dielectric and ferroelectric investigations for these specimens were performed. X-ray measurements showed that all compositions have a single perovskite structure with orthorhombic symmetry. Dielectric study revealed that the ceramics obtained are normal ferroelectrics. However some signs of diffuse phase transition were observed. The transition temperatures and the maximum electric permitti…
Influence of Uniaxial Pressure on Dielectric Properties of the PLZT-x/65/35 (x = 11 and 13) Ceramics
Uniaxial pressure (0–1000 bars) effects on the dielectric properties of the PLZT-x/65/35 ceramic samples (x = 11 and 13) samples was investigated. The obtained results reveal that the applied stress largely changes the dielectric properties of these ceramics. Applying uniaxial pressure leads to a reduction of the peak intensity of the electric permittivity and a change of the frequency dispersion. Besides with increasing the pressure the ϵ-peak shifts to a higher temperature. The results show that applying the uniaxial pressure induces similar effects as increasing the Ti−ion concentration in PZT system. These effects can be connected with the change in domain structure under the action of …
Influence of uniaxial pressure and aging on dielectric and ferroelectric properties of BaTiO3ceramics
The effect of uniaxial pressure (0–3000 bar) applied parallel to the AC electric field and aging on dielectric and ferroelectric behavior of BaTiO3 ceramics were investigated. Applying uniaxial pressure leads to a reduction of the peak intensity of the electric permittivity (e) of the polarization as well as of the dielectric hysteresis. The peak intensity of e becomes diffused and shifts to a higher temperatures with increasing the pressure. The electrostrictive coefficient Q 11 and differential permittivity were evaluated from the obtained data. We interpreted our results based on the hardening of the soft-mode and domain switching processes under the action of pressure. The aging effect …