Athipong Ngamjarurojana

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⟩.

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.

Dynamic ferroelectric hysteresis scaling of BaTiO3 single crystals

The scaling behavior of the dynamic hysteresis of ferroelectric BaTiO3 single crystals was investigated. Two sets of the scaling relation of hysteresis area ⟨A⟩ against frequency f and field amplitude E0 were clearly established. Above the coercive field, the scaling took a form of ⟨A⟩∝f−0.195E00.950. On the other hand, the scaling in the form of ⟨A⟩∝f1.667E0−2.804E04.157 was obtained under subcoercive field condition. While these scaling relations were generally comparable to previously reported ones, it was found that the f and E0 exponents depended on E0 and f, respectively, which was in contrast to the prior theoretical prediction and experimental investigations.

Dielectric Properties of BaTiO3-Modified BiFeO3 Ceramics

Multiferroic BiFeO3 has attracted extensive interest due to its potential in several applications. However, pure-phase BiFeO3 is very difficult to obtain. Hence, mixing BiFeO3 with other ferroelectrics, such as BaTiO3, is another approach to obtain materials with possible multiferroic properties. In this study, the BiFeO3 was modified with addition of BaTiO3 via a simple solid state reaction method. Dielectric properties of the BaTiO3-modified BiFeO3 ceramics were investigated over wide range of temperature and frequency. The results show that the (1-x)BiFeO3-xBaTiO3 ceramics with x = 0.1 and 0.2 exhibited large dielectric properties with giant-dielectric-like behavior. The dielectric properties were seen to improve with increasing BaTiO3 content, with the highest dielectric constant (ϵr = 19000) observed in 0.8BiFeO3-0.2BaTiO3 ceramic. The results were explained in terms of the pre-dominantly intrinsic BiFeO3 giant-dielectric behavior as a result of Fe multivalent states, as well as a better grain packing density with increasing BaTiO3 content.

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.

Changes in dielectric and ferroelectric properties of Fe3+/Nb5+ hybrid-doped barium titanate ceramics under compressive stress

The influences of compressive stress on the dielectric and ferroelectric properties of Fe3+/Nb5+ hybrid-doped barium titanate (BaTiO3) ceramics were investigated. Superimposed compressive stress had a pronounced effect on the electrical properties of the ceramics. The response of low-field dielectric properties to stress changed from soft to hard piezoelectric behavior with increasing Nb5+ content. While ferroelectric properties decreased with stress, hardening behavior was observed with increasing Nb5+ content in hybrid-doped BaTiO3 ceramics. A mechanism based on induced change in the acceptor valence by the donor dopant in hybrid-doped BaTiO3 ceramics was proposed to explain the results obtained.

Changes in ferroelectric properties of ceramics in lead magnesium niobate–lead titanate system with compressive stress

Effects of compressive stress on the ferroelectric properties of Pb(Mg1/3Nb2/3)O3–PbTiO3 (PMN-PT) ceramics were investigated. The ceramics with the formula (1−x)Pb(Mg1/3Nb2/3)O3−(x)PbTiO3 or (1−x)PMN−(x)PT (x=0.1–0.5) were prepared by a conventional mixed-oxide method. Dense perovskite-phase PMN-PT ceramics with a uniform microstructure were obtained. The ferroelectric properties were measured under compressive stress (0–75 MPa) using a homebuilt compressometer in conjunction with a modified Sawyer–Tower circuit. The experimental results revealed that the superimposed compression stress significantly reduced both the dissipation energy and the polarizations of the near morphotropic phase boundary compositions, i.e., 0.8PMN-0.2PT, 0.7PMN-0.3PT, and 0.6PMN-0.4PT, while the stress influence was much less in other compositions. On the contrary, the applied compressive stress showed little or no influence on the coercive field. These results were interpreted through the non-180° ferroelastic domain switching p...

Acoustic and Piezoelectric Properties of 0-3 Barium Zirconate Titanate-Portland Cement Composites-Effects of BZT Content and Particle Size

Lead-free 0-3 Barium zirconate titanate (BZT)-Portland cement (PC) composites, environmentally friendly piezoelectric materials, which are expected to find applications in smart concrete structures due to their good compatibility with the host concrete, are studied. The results indicate that the composites can be tuned to a compatible value to match the requirement of concrete structure. For 425 μm BZT particle size used for the range tested at the same volume led to optimum piezoelectricity in composites. The electromechanical coupling coefficient was found to be ≈17% for 70% BZT composite. Several mathematical models are applied for the calculation of the piezoelectric coefficient of the composites and the experimental results were closest to those calculated from the cube model.

Stress-dependent scaling behavior of subcoercive field dynamic ferroelectric hysteresis in Pb(Zn1/3Nb2/3)O3-modified Pb(Zr1/2Ti1/2)O3 ceramic

Scaling behavior of subcoercive field dynamic ferroelectric hysteresis under influence of stress was investigated in Pb(Zn1∕3Nb2∕3)O3-modified Pb(Zr1∕2Ti1∕2)O3 (PZT) bulk ceramic. The scaling relation of hysteresis area ⟨A⟩ against frequency f, field amplitude E0, and stress σ for the minor loops takes a form of ⟨A−Aσ=0⟩∝f−0.42E03.65σ0.24, which is very similar to that of soft and hard PZT ceramics. However, slightly faster responses to f and E0 indicate the ease of polarization orientation in this simpler domain structure ceramic as compared to commercial PZT ceramics.

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.