Q. R. Yin

Electron acoustic imaging of BaTiO3 single crystals

Scanning electron acoustic microscopy (SEAM) has been used in the observation of ferroelectric domain configurations in barium titanate single crystals. The contribution to the image contrasts is related to signal generation through a piezoelectric coupling mechanism. The results prove that SEAM really has the ability to show not only the surface shape and domain structures but also the subsurface domain structures. Furthermore, SEAM is a convenient, fast and nondestructive way of observing the ferroelectric domains compared with other methods.

Intergrowth Bi2WO6–Bi3TiNbO9 ferroelectrics with high ionic conductivity

This work was supported by the Ministry of Science and Technology of China through 973-Project under Grant No. 2002CB613307.

Lanthanum distribution and dielectric properties of intergrowth Bi5-xLaxTiNbWO15 ferroelectrics

This work was supported by the Ministry of Science and Technology of China through 973-Project under Grant No. 2002CB613307.

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.

Ferroelectricity in intergrowth Bi3TiNbO9–Bi4Ti3O12 ceramics

Monophase intergrowth Bi{sub 3}TiNbO{sub 9}-Bi{sub 4}Ti{sub 3}O{sub 12} (BTN-BIT) ceramics were synthesized by solid-state reaction method. In the temperature dependence of dielectric permittivity, two anomalies appeared at 945 and 1114 K, respectively. The ferroelectric hysteresis loop measurement revealed that the 2P{sub r} is 20 {mu}C/cm{sup 2}, nearly as twice as that of the BTN ceramic. The crystal structure analysis indicated that the enhanced octahedral distortion along the a axis is the main contribution to the ferroelectricity of BTN-BIT. The increased 2P{sub r} for the BTN-BIT ceramics is ascribed to its larger P{sub s} than that of the BTN and easier domain switching under electric field than that of the BIT.Monophase intergrowth Bi3TiNbO9–Bi4Ti3O12 (BTN-BIT) ceramics were synthesized by solid-state reaction method. In the temperature dependence of dielectric permittivity, two anomalies appeared at 945 and 1114K, respectively. The ferroelectric hysteresis loop measurement revealed that the 2Pr is 20μC∕cm2, nearly as twice as that of the BTN ceramic. The crystal structure analysis indicated that the enhanced octahedral distortion along the a axis is the main contribution to the ferroelectricity of BTN-BIT. The increased 2Pr for the BTN-BIT ceramics is ascribed to its larger Ps than that of the BTN and easier domain switching under electric field than that of the BIT.

Scanning electron-acoustic imaging of residual stress distributions in aluminum metal and ZrSiO4 multiphase ceramics

The scanning electron-acoustic imaging technique has been used in the characterization of the residual stress field distributions existing in the subsurface in aluminum disks and 20 vol % SiC ( w)/ZrSiO4 multiphase ceramics left by Vicker’s indentation. The experimental results reveal that the distribution areas are the plastic-elastic interchange zones. The electron-acoustic signal generation mechanism in the samples are discussed.

Dielectric and ferroelectric properties of intergrowth Bi7−xLaxTi4NbO21 ceramics

This work was supported by the Ministry of Science and Technology of China through 973-Project No. 2002CB613307, the National Natural Science Foundation of China No. 50572113, and Shanghai Commission of Science and Technology No. 05JC14079.

Ultrahigh piezoelectric response perpendicular to special cleavage plane in BaTiO3 single crystals

We report on the ultrahigh piezoelectric response perpendicular to some special cleavage plane in BaTiO3 single crystals. An extremely high value of piezoelectric coefficient d33 value over 2000pC∕N was obtained after being poled perpendicular to special plane (270) in BaTiO3 crystal, which is more than 20 times higher than those poled along spontaneous polarization direction ⟨001⟩ (d33⟨001⟩=87pC∕N). A large strain of 0.6% was obtained at a very low electric field.

Effect of La content on characterization of PLZT ceramics

Abstract This work has been undertaken with a view to study the effect of lanthanum content on properties of PLZT ceramics. The polycrystalline complex compounds of PLZT with Pb1−xLax(Zr0.40Ti0.60)1−x/4O3, +10% PbO formula were prepared from the nano-size individual oxides powders by hot-pressed process. Transparent PLZT (x/40/60) bulk ceramics with pure tetragonal phase was obtained. The studies of the microstructures, dielectric and ferroelectric properties of the ceramics were carried out. The experiment results showed that when La content increased from 7 to 13 mol.%, the grain size increased from 2 to 7 μm. La content also effects the dielectric property obviously, the dielectric constant increased with La content increasing. Moreover, the ferroelectric properties are sensitive to the variation of La content.

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.