N. Triamnak

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.

Stress dependence and scaling of subcoercive field dynamic hysteresis in 0.5Pb(Zr1/2Ti1/2)O3–0.5Pb(Zn1/3Nb2/3)O3 ceramic

Stress dependence and scaling behavior of subcoercive field dynamic ferroelectric hysteresis were investigated in rhombohedral 0.5Pb(Zr1/2Ti1/2)O3–0.5Pb(Zn1/3Nb2/3)O3 (0.5PZT–0.5PZN) bulk ceramic with profound relaxor characteristics. 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−0.34E03.68σ0.35, which is very similar to that of soft and hard lead zirconate titanate ceramics with the same disrupted domains. This study suggests that the domain structures play a significant role in controlling the dynamic hysteresis behavior of ferroelectric materials.

Power-law scaling of sub-coercive field dynamic hysteresis response in 0.7Pb(Zr1/2Ti1/2)O3–0.3Pb(Zn1/3Nb2/3)O3 ceramic

Scaling behaviour of sub-coercive field dynamic ferroelectric hysteresis under the influence of stress was investigated in rhombohedral 0.7PZT–0.3PZN bulk ceramic. The scaling relation of hysteresis area A against frequency f, field amplitude E0 and stress σ for the minor loops takes the form of , 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 with commercial PZT ceramics. This study suggests that the domain structures play a significant role in controlling dynamic hysteresis behaviour of ferroelectric materials.

Effects of Iron Addition on Electrical Properties and Aging Behavior of Barium Titanate Ceramics

In this study, the influences of Fe addition on phase formation and electrical properties of Ba(Ti 1 − x Fe x )O 3 with x = 0 to 0.02 were investigated. In addition, aging behavior of the ceramics was also investigated. The XRD analysis showed that the crystal structure of Ba(Ti 1 − x Fe x )O 3 changed from tetragonal to hexagonal as Fe concentration increased to x = 0.015, causing a noticeable decrease in the dielectric properties. From ferroelectric hysteresis (P-E) loops measurements, with increasing Fe content the saturation polarization decreased, while the coercive electric field increased at low concentration (x ≤ 0.01) with tetragonal structure. At x ≥ 0.015, with paraelectric hexagonal phase, no P-E hysteresis loop was observed at room temperature. Room temperature aging study showed that the ferroelectric P-E hysteresis loops became constricted loops during aging in Ba(Ti1 − x Fe x )O 3 with ferroelectric tetragonal phase. The dielectric constant also decreased during aging.

Scaling and stress dependence of sub-coercive field dynamic hysteresis in 0.6Pb(Zr1/2Ti1/2)O3–0.4Pb(Zn1/3Nb2/3)O3 ceramic

The scaling behavior of sub-coercive field dynamic ferroelectric hysteresis under the influence of stress was investigated in rhombohedral 0.6Pb(Zr0.5Ti0.5)O3–0.4Pb(Zn1/3Nb2/3)O3 (0.6PZT–0.4PZN) bulk ceramic. The scaling relation of hysteresis area against frequency f, field amplitude E0, and stress σ for the minor loops takes the form of , indicating the difference in the energy dissipation between the stressed and stress-free conditions. While the scaling obtained is very similar to that of soft and hard PZT ceramics, slightly faster responses to f and E0 indicate the ease of polarization orientation in this ceramic with a simpler domain structure compared to commercial PZT ceramics. However, the difference in mechanical properties of these materials could contribute to a variation in the response to stress. While the E0 exponent obtained in this study agreed well with that derived from the Monte Carlo simulation based on the Q-state planar Potts model, the difference in the f exponent obtained experimentally and theoretically was attributed to the depolarizing effects presented in the bulk ceramics.

Dielectric Properties of Pb(Zr1/2Ti1/2)O3−Pb(Zn1/3Nb2/3)O3 Ceramics Under Compressive Stress

Effects of compressive stress on the dielectric properties of PZT-PZN ceramics with a formula (1−x) Pb(Zr 1/2 Ti 1/2 )O 3 −xPb(Zn 1/3 Nb 2/3 )O 3 or (1−x) PZT-(x)PZN(x = 0.1–0.5) were investigated under stress up to 230 MPa. The experimental results revealed that the superimposed compression stress had pronounced effects on both the dielectric constant and the dielectric loss tangent of PZT-PZN ceramics. In addition, the dielectric properties were considerably lowered after a stress cycle. The observations were mainly interpreted in terms of domain switching through non-180° domain walls, clamping of domain walls, de-aging, and the stress induced decrease in switchable part of spontaneous polarization.

Stress-Dependent Scaling Behavior of Sub-Coercive Field Dynamic Hysteresis in Pb(Zr1/2Ti1/2)O3–Pb(Zn1/3Nb2/3)O3 Ceramic Systems

Stress dependence and scaling behavior of sub-coercive field dynamic ferroelectric hysteresis were investigated in (1-x)PZT-(x)PZN bulk ceramics, where x = 0.1, 0.2, 0.3, 0.4, and 0.5. The results shown that hysteresis area < A >, remnant polarization (P r ), and coercive field (E C ) increase with increasing of field amplitude (E 0), while decrease with increasing of frequency and compressive stress similar to previous investigations in bulk ceramics. The scaling relations of hysteresis area < A > against frequency f, field amplitude E 0, and stress σ for the minor loops took a form of < A–A σ = 0> ∝ f α E 0 β σγ with range of (−0.42) to (−0.34), (3.32) to (4.03), and (0.19) to (0.38) for exponents α, β, and γ, respectively, depending on compositions, which are very similar to that of soft and hard PZT bulk ceramics. This study suggests that the domain structures play a key role in controlling dynamic hysteresis behavior of ferroelectric materials.

Effects of Iron Addition on Aging Behavior of Barium Titanate Ceramics under Compressive Stress

In this study, a room temperature aging behavior of Ba(Ti0.99Fe0.01)O3 was investigated. It was found that the dielectric constant decreased with time and ferroelectric P-E hysteresis loops became constricted loops after aging. Moreover, the room temperature aging behavior under various stresses was also observed. It was found that the relative changes of dielectric constant with time of Ba(Ti0.99Fe0.01)O3 ceramics under stress were lower than those under the stress-free condition. For P-E hysteresis loop measurement, it can be observed that P-E hysteresis loop of Ba(Ti0.99Fe0.01)O3 ceramics became constricted loops and remanant polarizations (Pr), saturated polarizations (Ps) were decreased after aging under all stress levels. These results suggested that the applied stress may partly clamp the domain wall motion, and altered the aging behavior of the ceramics.