Supattra Wongsaenmai

Scaling behavior of dynamic hysteresis in soft lead zirconate titanate bulk ceramics

The scaling behavior of the dynamic hysteresis of ferroelectric bulk system was investigated. The scaling relation of hysteresis area ⟨A⟩ against frequency f and field amplitude E0 for the saturated loops of the soft lead zirconate titanate bulk ceramic takes the form of ⟨A⟩∝f−1∕4E0, which differs significantly from that of the theoretical prediction and that of the thin film. This indicates that the scaling relation is dimension dependent and that depolarizing effects in the interior must be taken into account to model bulk materials. Additionally, the scaling relation for the minor loops takes the form of ⟨A⟩∝f−1∕3E03, which is identical to that of the thin film as both cases contain similar 180° domain-reversal mechanism.

Temperature scaling of dynamic hysteresis in soft lead zirconate titanate bulk ceramic

The temperature scaling of the dynamic hysteresis was investigated in soft ferroelectric bulk ceramic. The power-law temperature scaling relations were obtained for hystersis area ⟨A⟩ and remnant polarization Pr, while the coercivity EC was found to scale linearly with temperature T. The three temperature scaling relations were also field dependent. At fixed field amplitude E0, the scaling relations take the forms of ⟨A⟩∝T−1.1024, Pr∝T−1.2322, and (EC0−EC)∝T. Furthermore, the product of Pr and EC also provides the same scaling law on the T dependence in comparison with ⟨A⟩.

Effect of uniaxial compressive pre-stress on ferroelectric properties of soft PZT ceramics

The effect of uniaxial compressive pre-stress on the ferroelectric properties of commercial soft PZT ceramics is investigated. The ferroelectric properties under the uniaxial compressive pre-stress of the ceramics are observed at stress up to 24 MPa using a compressometer in conjunction with a modified Sawyer–Tower circuit. The results show that the ferroelectric characteristics, i.e. the area of the ferroelectric hysteresis (P–E) loops, the saturation polarization (Psat), the remanent polarization (Pr), and the loop squareness (Rsq) decrease with increasing compressive pre-stress, while the coercive field (Ec) is virtually unaffected by the applied stress. The stress-induced domain wall motion suppression and non-180° ferroelectric domain switching processes are responsible for the changes observed. In addition, a significant decrease in these parameters after a full cycle of stress application has been observed and attributed to the stress-induced decrease in the switchable part of the spontaneous polarization at high stress. Furthermore, the permittivity calculated from the P–E loops is found to decrease with increasing applied pre-stress. This finding differs considerably from the results in the low-field experimental condition. Finally, this study clearly shows that the applied stress has a significant influence on the ferroelectric properties of soft PZT ceramics.

Effects of uniaxial stress on dielectric properties lead magnesium niobate?lead zirconate titanate ceramics

Effects of uniaxial stress on the dielectric properties of ceramics in lead magnesium niobate?lead zirconate titanate (PMN?PZT) system are investigated. The ceramics with a formula (x)Pb(Mg1/3Nb2/3)O3?(1?x)Pb(Zr0.52Ti0.48)O3 or (x)PMN?(1 ? x)PZT when x = 0.0, 0.1, 0.3, 0.5, 0.7, 0.9, and 1.0 are prepared by a conventional mixed-oxide method. Phase formation behaviour and microstructural features of these ceramics are studied by x-ray diffraction and scanning electron microscopy methods, respectively. The dielectric properties under the uniaxial stress of the PMN?PZT ceramics are observed at stress levels up to 5?MPa using a uniaxial compressometer. It is found that with increasing applied stress the dielectric constant of the PZT-rich compositions increases slightly, while that of the PMN-rich compositions decreases. On the other hand, the dielectric loss tangent for most of the compositions first rises and then drops with increasing applied stress.

Dynamic hysteresis and scaling behavior of hard lead zirconate titanate bulk ceramics

The scaling relation of ferroelectric hysteresis area ⟨A⟩ against frequency f and field amplitude E0 for the saturated loops of the hard lead zirconate titanate bulk ceramic takes the form of ⟨A⟩∝f−0.28E00.89, while that for the minor loops takes the form of ⟨A⟩∝f−0.43E03.19. In both cases, the scaling relations are similar to those of its soft counterpart. This indicates that the dynamic behaviors and scaling relations in bulk ceramics are mainly governed by the domain states and structures, while the distinct types of complex defects contribute mainly to the difference in the coercive field observed in hard and soft ceramics.

Stress-dependent scaling behavior of dynamic hysteresis in bulk soft ferroelectric ceramic

The effects of frequency f, field amplitude E0, and mechanical stress σ on the hysteresis area ⟨A⟩ and their scaling relations were investigated on soft PZT bulk ceramics. The hysteresis area was found to depend on the frequency and field amplitude with a same set of exponents to the power-law scaling for both with and without stresses, indicating the universality. The inclusion of stresses into the power law was also obtained in the form of ⟨A−Aσ=0⟩∝f−0.25E0σ0.44, which indicates the difference of the energy dissipation between the under stress and stress-free conditions and reveals how the hysteresis area decays with increasing stresses.

Stress- and temperature-dependent scaling behavior of dynamic hysteresis in soft PZT bulk ceramics

Effects of electric field-frequency, electric field-amplitude, mechanical stress, and temperature on the hysteresis area, especially the scaling form, were investigated in soft lead zirconate titanate (PZT) bulk ceramics. The hysteresis area was found to depend on the frequency and field-amplitude with the same set of exponents as the power-law scaling for both with and without stresses. The inclusion of stresses into the power-law was obtained in the form of which indicates the difference in energy dissipation between the under-stress and stress-free conditions. The power-law temperature scaling relations were obtained for hysteresis area A and remanent polarization Pr, while the coercivity EC was found to scale linearly with temperature T. The three temperature scaling relations were also field-dependent. At fixed field amplitude E0, the scaling relations take the forms of , Pr ∝T−1.2322 and (EC0 - EC) ∝T.

Scaling Behavior of Dynamic Ferroelectric Hysteresis in Soft PZT Ceramic: Stress Dependence

Effects of electric field-frequency, electric field-amplitude, and mechanical stress on the hysteresis area were investigated on soft PZT ceramic. At stress-free condition, the investigation found the area scales with frequency and field-amplitude in power-law form, ⟨A⟩ ∝ ƒ−0.25 E 0; however, with different set of exponents in comparing to those in the investigation on thin films structure. On the other hand, with compressive stresses turning on, the same set of the exponents with the stress-free condition is found to confirm universality. In addition, the scaling form of the area to triple parameters; i.e., frequency, field-amplitude, and stress in a power law form, ⟨A⟩ − ⟨A σ = 0⟩ = ⟨ A − A σ = 0⟩ ∝ ƒ− 0.25 E 0 σ 0.44 , was obtained.

Dielectric properties and relaxor behavior of PIN based system

Several compositions in the two PIN based systems (1-x)Pb(In0.5Nb0.5)O3-(x)PbTiO3 and (0.8-x)Pb(In0.5Nb0.5)O3-(x)PbTiO3–0.2BaTiO3 (x = 0.0, 0.1, 0.2 and 0.3) were synthesized via the wolframite method. Dielectric properties were measured in the frequency range between 100 Hz and 100 kHz and were analyzed for understanding relaxor behavior in the system. The temperature dependence of the dielectric properties was analyzed by studying the deviation from the Curie-Weiss law while the frequency dependence of the dielectric properties was analyzed by the Vogel-Fulcher relation. The results showed that the addition of BT increased the dielectric constant and decreased the shift of the maximum dielectric constant temperature (Tm) of (1-x)PIN-(x)PT compositions. Finally, the analysis also confirmed that, when added to PIN, PT decreased and BT increased the relaxor behavior of the PIN-based ceramics.

Changes in dielectric properties of Pb(In1/2Nb1/2)O3-PbTiO3 ceramics under compressive stress applied parallel and perpendicular to an electric field

The influences of compressive stress on the dielectric properties of (1 ? x)Pb(In1/2Nb1/2)O3?xPbTiO3 (x = 0.1?0.5) ceramics was investigated in this study. The dielectric properties were measured under compressive stress applied parallel and perpendicular to electric field. The results clearly showed that the superimposed compression stress had pronounced effects on the dielectric properties of PIN?PT ceramics. In general, with increasing compressive stress the dielectric constant of the ceramics increased and decreased when the stress was applied parallel and perpendicular, respectively, to the electric field direction. The dielectric loss tangent, however, decreased in both stress cases. The observations were mainly interpreted in terms of competing influences of the domain switching through non-180? domain walls, clamping of domain walls, de-ageing and the stress-induced decrease in the switchable part of spontaneous polarization.