G.R. Li

Abnormal piezoresponse behavior of Pb(Mg1/3Nb2/3)O3–30%PbTiO3 single crystal studied by high-vacuum scanning force microscope

The piezoresponse behavior dependence of the Pb(Mg1/3Nb2/3)O3-30%PbTiO3 single crystal on the vacuum degree has been investigated by scanning force microscopy in the piezoresponse mode under high vacuum. Unusual piezo-response behavior related to the screening charges compensation mechanism is observed on the (111) crystal face. The significant piezoresponse degradation behavior with low piezoresponse signal under high vacuum is attributed to the instability of the polarization state due to the insufficient compensation of the intrinsic screening charges for the polarization charges in PMN-30%PT single crystal. In contrast, the remarkable domain contrast of the sample at ambient pressure is owing to the dominant surface screening charges deriving from surface adsorption, which plays an important role in determining the stability of the domain behavior and in achieving the optimal properties.

The influence of PbZrO3/PbTiO3 ratio on diffuse phase transition of Pb(Zn1/3Nb2/3)O3-PbZrO3-PbTiO3 system near the morphotropic phase boundary

The diffuse phase transition of Pb(Zn1/3Nb2/3)O3–PbZrO3–PbTiO3 (PZN–PZ–PT) ternary solid solution near the rhombohedral/tetragonal morphotropic phase boundary (MPB) is reported in this paper for the first time. All compositions near MPB exhibit a relaxor behavior around dielectric permittivity peak. It is found that the extent of diffuse phase transition of PZN–PZ–PT increases with the increases of PbZrO3/PbTiO3 ratio.

Distribution and formation mechanism of the domain structure in PMN?33% PT single crystals

Domain structures investigation in (110)-oriented Pb(Mg1/3Nb2/3)O3–33% PbTiO3 (PMN–33% PT) single crystals has been performed by piezoresponse force microscopy. Submicron-sized fingerprint pattern and tweed pattern domains (TPDs) have been observed in large parallel domains with typical sizes of 20–30 µm. Based on the existence of gradual transition regions between fingerprint pattern domains and TPDs in the same large ferroelectric domain, the relationship between the two pattern domains is discussed and a possible formation mechanism of the domain structure in PMN–33% PT single crystal is proposed.

Local characterization of compositionally graded Pb(Zr,Ti)O3 thin films by scanning force microscope

Abstract Compositionally graded PZT thin film was prepared by a sol–gel technique. Nanoscale domain structure and polarization reversal behavior in an individual grain were investigated by means of scanning force microscopy (SFM) in piezoresponse mode. Domain as small as 30 nm in size was visualized. The observed complex domain contrast was attributed to the crystallographic orientation of the grains and to the built-in potential difference in compositionally graded PZT thin film under an ac field. The built-in potential difference, defect and space charge gave rise to strong domain pinning behavior during the polarization reversal.

ELECTRICAL PROPERTIES OF LAYER STRUCTURED BI4Ti3O12 FERROELECTRICS WITH W6+ DOPING

ABSTRACT W6+-doped Bi4Ti3O12 (BIT-W) layer structured ferroelectric ceramics have been prepared and electrical properties were investigated. The electrical resistivity of BIT-W ceramics in a direct current circuit was increased obviously by W6+-doping. The ac complex impedance plot of BIT-W is different from that of undoped Bi4Ti3O12, indicating different effects of grains, grain boundaries and ferroelectric-electrode interfaces. Hysteresis loops of BIT-W were studied. W6+-doping enhances the remnant polarization because the domain pinning effect caused by oxygen vacancies reduced. Thermally stimulated depolarization current results indicated that the piezoelectric properties of BIT-W came from the polarization of intrinsic dipoles and defect dipoles.

Piezoelectric Force Microscope Investigation and Ferroelectric Hysteresis Behavior of High Volume Piezoelectric Ceramic in 0–3 Lead Zirconate Titanate-Cement Composites

Piezoelectric lead zirconate titanate (PZT) ceramic-cement composites using a high volume of ceramic content (80%) in 0–3 connectivity were fabricated. Piezoelectric Force Microscope (PFM) characterization was carried out and ferroelectric hysteresis behavior of the composites were investigated. Domain configurations of PZT ceramic can be seen at the interfacial zone of PZT-cement composites. Ceramic particles were seen to bind well with the cement matrix. The ferroelectric hysteresis loop at 50 Hz and 10–25 kV/cm showed a slim loop with low loss behavior for this type of composite due to increase in the PZT ceramic in 0-3 PZT-cement composites.

Near-field acoustic microscopy of ferroelectrics and related materials

Ferroelectric ceramics and crystals, semiconductor on insulator material and MEMS device have been observed in scanning electron acoustic microscope. The images demonstrate the ability of the microscope to image surface texture, subsurface defect, domain structure and to penetrate opaque layers non-destructively. Ferroelectric domains viewed by scanning probe acoustic microscope based on atomic force microscope are also presented in order to compare both near-field acoustic techniques.

Dielectric/ferroelectric and phase transition properties of PLZT ceramics

ABSTRACT The La doped ceramics PLZT-0.03/1-x/x (0.43 ≤ x ≤ 0.49) around morphotropic phase boundary (MPB) region were prepared by solid-state reaction. The ceramics exhibited diffused phase transition behavior, while MPB region showed the least degree of diffusion. It has been shown that distinct difference exists between poled and unpoled samples. All the samples exhibited thermal hysteresis behavior characteristic of the first order phase transition. The ferroelectric properties of the samples were also discussed.

Investigations on Morphology and Domain Configurations in 0–3 Lead Magnesium Niobate Titanate–Portland Cement Composites by SEM and PFM

Lead magnesium niobate titanate (PMNT) and Portland cement (PC) composite were fabricated as a new cement-based piezoelectric composite. Scanning Electron Microscope and Piezoresponse Force Microscope were used to investigate the morphology and domain configurations at the interfacial zone of PMNT-PC composites. Angular PMNT ceramic grains were found to bind well with the cement matrix and PMNT grains can be seen to disperse randomly in the cement matrix. Moreover, the angular shape PMNT particle contributes to better mechanical interlocking with the cement paste due to the angular aggregate having rough surface appearing to provide better mechanical interlocking with the cement paste.

Enhancement of Piezoelectric Properties of PMN-PT Ceramics at Low Temperatures

The temperature dependence of dielectric, elastic, electromechanical, and piezoelectric properties of (1-x)Pb(Mg1/3Nb2/3)O3-xPbTiO3 (PMN-xPT) ceramics near MPB with x = 0.33, 0.35, 0.36, 0.37, and 0.38 was systematically investigated within the temperature range 120–360 K. Compositions of x = 0.37 and 0.38 were found to exhibit temperature-independent piezoelectric properties over a temperature range from 185 to 360 K. The temperature-stable piezoelectric response was attributed to a counter-balance among the dielectric, elastic, and electromechanical responses in a broad ferroelectric phase transition that was revealed from the dielectric constant, elastic compliance constant, and electromechanical coupling factor.