Processing, basic characterization and standard dielectric measurements on PLZTx/65/35 (4 ≤x≤ 11) ceramics
The influence of external stress (0–800 bar) on the dielectric properties of lead lanthanum zirconium titanate (PLZT) x/65/35 (4 ≤ x ≤ 11) ceramics was investigated. Applying uniaxial pressure leads to a change in the peak intensity of the electric permittivity (ϵ), in its frequency dispersion as well as in the dielectric hysteresis. The peak intensity of ϵ becomes broader and shifts to lower temperatures for PLZT x/65/35 with x = 4, 7, 9.75 and 11, with increasing pressure, on heating. It was concluded that applying uniaxial pressure induces an increase of Tm, and thus has a similar effect as the increase of the Ti ion concentration in the lead zirconium titanate (PZT) system. Results base…
Influence of Electromechanical Fields on Dielectric Properties of PLZT−x/65/35 Ceramics (x = 6 and 7)
High density and transparent PLZT−x/65/35 (x = 6 and 7) ceramics with the average grain size of 5–7 μm was obtained by two−stage hot−pressing technology. The measurements of temperature/frequency dependence of the permittivities of these ceramics under uniaxial pressure (0–100 MPa) applied parallel to the ac electric field have been carried out. It was found that uniaxial pressure significantly influences dielectric properties of these ceramics. With the increase of pressure the maximum intensity in ϵ(T) curve decreases, becomes more diffuse and shifts towards higher temperature, dielectric dispersion decreases and classical ferroelectric seems to change to relaxor one. It was concluded, th…
LEAD-FREE (Na0.5Bi0.5)1-xBaxTiO3 SINGLE CRYSTALS (0 ≤ x ≤ 0.05) AND THEIR DIELECTRIC AND PYROELECTRIC PROPERTIES
ABSTRACT Lead-free single crystals of Na0.5Bi0.5TiO3-BaTiO3 (NBT-BT) system were prepared by Czochralski method and their dielectric and pyroelectric properties have been studied. The results were compared with these for pure NBT. The obtained samples show pure perovskite structure with rhombohedral symmetry at room temperature. Low frequency (100 Hz–100 kHz) investigations reveal the diffuse phase transitions. The obtained results are discussed in terms of local electric and strain fields caused by different ionic radius of (Na, Bi) and Ba ions. The NBT-BT system is expected to be a new promising candidate for lead-free electronic crystals.
Dielectric Properties of Na0.5K0.5(Nb1-xSbx)O3+MnO2 Ceramics (x = 0.04, 0.05 and 0.06)
Lead-free ceramics Na0.5K0.5(Nb1-xSbx)O3+0.5mol%MnO2 (x = 0.04, 0.05 and 0.06) were prepared by conventional sintering and hot pressing process; their microstructure and dielectric properties have been studied. It is found that increase of sintering temperature promotes the obtaining highly dense microstructure and increase in grain size while doping with Sb contributes to more dense and homogeneous microstructure and smaller grain size. Low frequency (100 Hz-200 kHz) investigations revealed the diffuse phase transitions. It can be concluded from experimental results that Sb doping improves dielectric properties. The obtained materials are expected to be promising candidates for lead-free e…
Processing, basic characterization and standard dielectric measurements on PLZT x/65/35 (2≤x≤13) ceramics
ABSTRACTThe influence of external stress (0-800bar) on the dielectric properties of PLZT x/65/35 (2≤x≤13) ceramics was investigated. Applying uniaxial pressure leads to a change in the peak intensity of the electric permittivity (ϵ), of its frequency dispersion as well as in the dielectric hysteresis. The peak intensity of ϵ becomes broader and shifts to lower temperatures for PLZT x/65/35 with x = 2, 4, 6, 7, 9.75, 10, 11 and 13, with increasing pressure, on heating. It was concluded that applying uniaxial pressure induces an increase of Tm, and thus has similar effects as the increase of the Ti ion concentration in the PZT system. Results based on nanoregion switching processes under comb…
Electrical Transport Properties of Lead−Free (Na0.5Bi0.5)1-xBaxZr0.04Ti0.96O3Ceramics (x = 0.06, 0.085, 0.1)
Lead-free ceramics (Na0.5Bi0.5)1-xBaxZr0.04Ti0.96O3 were prepared by solid phase hot pressing sintering process. Density values of obtained samples are higher than 95% of the theoretical ones. Samples with x = 0.06, 0.085 and 0.1 were investigated in the present work. For these samples both ac and dc electric conductivity were studied. A low frequency (100 Hz-100 kHz) ac conductivity obeys the power law, characteristic for disordered materials. The dc conductivity has a thermally activated character. A barrier hopping model is found to explain the mechanism of charge transport in these materials. The (Na0.5Bi0.5)1-xBaxZr0.04Ti0.96O3 system is expected to be a new and promising candidate for…
Effect of Electromechanical Loading on the Dielectric Properties of PLZT−x/65/35 Ceramics (x = 8 and 8.5)
The influence of uniaxial pressure (0-800 bars) applied parallel to the ac electric field on the dielectric properties of La−modified lead–zirconate−titanate ceramics with the Zr/Ti ratio of 65/35 was investigated. Applying uniaxial pressure leads to the reduction of the peak intensity of the electric permittivity (ϵ), of the frequency dispersion as well as of the dielectric hysteresis. The peak intensity of ϵ becomes diffuse and shifts with increasing the pressure. Our results show that applying uniaxial pressure induces similar effects as increasing the Ti−ion concentration in PZT system. We interpreted our results based on domain switching processes under the action of combined electrome…
PLZTx/65/35 ceramics (x = 2 and 4) under electromechanical and temperature loading
The effect of uniaxial pressure (0–1000 bars) applied parallel to the ac electric field on dielectric properties of La-modified lead–zirconate–titanate, Pb(Ti,Zr)O3 (PZT), ceramics with Zr/Ti ratio of 65/35 was investigated. The experimental results revealed that applying uniaxial pressure leads to a reduction of the peak intensity of the electric permittivity (e), of the frequency dispersion as well as of the dielectric hysteresis. Moreover, with increasing pressure, the peak intensity of e becomes diffuse and shifts to a higher temperature. It was concluded that applying uniaxial pressure induces similar effects as increasing the Ti–ion concentration in PZT system. The obtained results we…
Uniaxial Pressure Effects on the Dielectric Properties of the PLZT-x/65/35 (x = 9.75 and 10) Ceramics
The influence of uniaxial pressure (0-1000 bars) applied parallel to the ac electric field on the dielectric properties of PLZT-x/65/35 ceramics (x = 9.75 and 10) was investigated. The results show that the applied stress has a significant influence on the dielectric properties of PLZT ceramics. Applying uniaxial pressure leads to the reduction of the electric permittivity (ϵ) peak and the frequency dispersion. Moreover, the peak of ϵ becomes diffuse and shifts to a higher temperature with increasing pressure. The results show that applying uniaxial pressure induces similar effects as the increase in Ti−ion concentration in the PZT system. We interpreted our results based on the domain swit…
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 …