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ABSTRACT: In this paper, a single crystal of 0.96Na0.5Bi0.5TiO3-0.04BaTiO3 with dimensions of Φ 30×10mm was grown by the top-seeded-solution growth method. X-ray powder diffraction results show that the as-grown crystal
possesses the rhombohedral perovskite-type structure. The dielectric, piezoelectric and electrical conductivity properties
were systematically investigated with 〈001〉, 〈110〉 and 〈111〉 oriented crystal samples. The room-temperature dielectric constants
for the 〈001〉, 〈110〉 and 〈111〉 oriented crystal samples are found to be 650, 740 and 400 at 1 kHz. The (T
m, ε
m) values of the dielectric temperature spectra are almost independent of the crystal orientations; they are (306°C, 3718),
(305°C, 3613) and (307°C, 3600) at 1kHz for the 〈001〉, 〈110〉 and 〈111〉 oriented crystal. The optimum poling conditions were
obtained by investigating the piezoelectric constants d
33 as a function of poling temperature and poling electric field. For the 〈001〉 and 〈110〉 crystal samples, the maximum d
33 values of 146 and 117 pC/N are obtained when a poling electric field of 3.5kV/mm and a poling temperature of 80°C were applied
during the poling process. The as-grown 0.96Na0.5Bi0.5TiO3-0.04BaTiO3 crystal possesses a relatively large dc electrical conductivity, especially at higher temperature, having a value of 1.98×10−11 Ω−1⋅m−1 and 3.95×10−9 Ω−1⋅m−1 at 25°C and 150°C for the 〈001〉 oriented crystal sample.
Applied Physics A 05/2012; 95(3):761-767. · 1.63 Impact Factor
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ABSTRACT: In this paper we fabricated the multilayer structure used as the resonance-based vibration energy-harvesting device based
on 0.71Pb(Mg1/3Nb2/3)O3–0.29PbTiO3 single crystal. The performances of the device including the output voltage and power were studied systematically. Under
a cyclic force of 4N (peak value), a high output power of 4.94mW and a corresponding peak voltage of 3.14V were measured
at 1.4kHz with a matching load resistance of 1.0kΩ. The results demonstrate the potential of the device in energy-harvesting
applied to low-power portable electronics and wireless sensors.
Applied Physics A 04/2012; 100(1):125-128. · 1.63 Impact Factor
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ABSTRACT: A 0.92Na0.5Bi0.5TiO3-0.08 K0.5Bi0.5TiO3 (0.92NBT-0.08KBT) lead-free piezoelectric single crystal with dimensions of Φ 35 × 10 mm was successfully grown by the top-seeded solution growth method. The effective segregation coefficient for K was calculated to be 0.27. An x-ray powder diffraction measurement showed that the as-grown crystal possesses a rhombohedral perovskite structure at room temperature. The room-temperature dielectric constants for poled 〈001〉, 〈110〉, and 〈111〉 oriented crystal samples are found to be 683, 567, and 435 at 1 kHz, respectively. The (Tm, ɛm) values for 〈001〉, 〈110〉, and 〈111〉 oriented crystals are (316 °C, 4318), (317 °C, 4160), and (318 °C, 4348) at 1 kHz, which indicate that the dielectric parameters of the as-grown crystals show weaker anisotropy. The curves, ɛ(T), for the three crystallographic orientations show two anomalies at about 170 and 320 °C, respectively, relating to the ferroelectric-antiferroelectric phase and the antiferroelectric-paraelectric phase. There is a thermal hysteresis, ΔT ≈ 35 °C for the ferroelectric-antiferroelectric phase transformation between heating and cooling. The antiferroelectric phase, the thermal hysteresis, and the dielectric relaxor behavior around 170 °C can be attributed to the formation of an intermediate orthorhombic modulated phase at 170–320 °C. For the 〈001〉, 〈110〉, and 〈111〉 crystal samples, the room-temperature piezoelectric constants, d33, reach 175, 130, and 70 pC/N, respectively. The remanent polarization for the 〈001〉, 〈110〉, and 〈111〉 crystal samples are 8.1, 10.8, and 13.5 μC/cm2, respectively, and the ratio is 1:1.33:1.67, close to 1::. The diffusive factors, α, are found to be 1.94, 1.91, and 1.50 for the 〈001〉, 〈110〉, and 〈111〉 oriented crystal samples, which indicate that the antiferroelectric-paraelectric phase transition of the as-grown 0.92NBT-0.08KBT crystal is a strong diffuse one. The electromechanical coupling coefficients for the 〈001〉, 〈110〉, and 〈111〉 oriented 0.92NBT-0.08KBT crystals at room temperature are 52, 50, and 48%, respectively. The values of kt for the three main crystallographic orientations change slightly with the increase of temperature from 15 to 140 °C, demonstrating a relatively stable thermal electromechanical coupling property.
Journal of Applied Physics 06/2011; 109(12):124113-124113-8. · 2.17 Impact Factor
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ABSTRACT: Much attention is drawn to the fundamental research and the applications of the relaxor-based ferroelectrics for the next generation of piezoelectric devices. Mass production of Pb(Mg1/3Nb2/3)O3–xPbTiO3 (PMNT) and ternary xPb(In1/2Nb1/2)O3–yPb(Mg1/3Nb2/3)O3–zPbTiO3 (PIMNT) single crystals with a Bridgman method was reported. The piezoelectric, pyroelectric, and electric–optical performances of PMNT single crystals are much more excellent than traditional ceramics with the composition near morphotropic phase boundaries. Compared with PMNT crystal, PIMNT crystals can be used in a more broad range of device applications due to their high Curie temperature Tc and large coercive fields Ec. A relaxor-based Na0.5Bi0.5TiO3–xBaTiO3 (NBBT) crystal grown by the top seeded solution growth method was also investigated to find a lead-free material with better piezoelectric performance. The properties of these relaxor-based single crystals were summarized. The mechanism of the enhanced piezoelectric response is discussed, based on the phase transitions induced by the variations of the temperature, pressure, composition, and electric field.
Journal of the American Ceramic Society 09/2010; 93(10):2915 - 2928. · 2.27 Impact Factor
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ABSTRACT: In this paper we theoretically and experimentally present a nonresonant vibration energy harvesting device based on the shear mode of 0.71Pb(Mg<sub>1/3</sub>Nb<sub>2/3</sub>)O<sub>3</sub>-0.29PbTiO<sub>3</sub> single crystals. The electrical properties of the energy harvesting device were evaluated using an analytical method. Good consistency was obtained between the analytical and experimental results. Under a mass load of 200 g, a peak voltage of 11.3 V and maximum power of 0.70 mW were obtained at 500 Hz when connecting a matching load resistance of 91 kΩ. A high output could always be obtained within a very wide frequency range. The results demonstrate the potential of the device in energy harvesting applied to low-power portable electronics and wireless sensors.
IEEE Transactions on Ultrasonics Ferroelectrics and Frequency Control 07/2010; · 1.69 Impact Factor
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ABSTRACT: In this paper we theoretically and experimentally present a nonresonant vibration energy harvesting device based on the shear mode of 0.71Pb(Mg(1/3)Nb(2/3))O3-0.29PbTiO3 single crystals. The electrical properties of the energy harvesting device were evaluated using an analytical method. Good consistency was obtained between the analytical and experimental results. Under a mass load of 200 g, a peak voltage of 11.3 V and maximum power of 0.70 mW were obtained at 500 Hz when connecting a matching load resistance of 91 komega. A high output could always be obtained within a very wide frequency range. The results demonstrate the potential of the device in energy harvesting applied to low-power portable electronics and wireless sensors.
IEEE transactions on ultrasonics, ferroelectrics, and frequency control 06/2010; 57(6):1419-25. · 1.80 Impact Factor
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ABSTRACT: In this letter we presented a cantilever beam used for vibration energy harvesting based on shear mode 0.71Pb(Mg1/3Nb2/3)O3–0.29PbTiO3 single crystal. The working principle of the device was inferred and the factors influencing the output were obtained using an analytical method. The electrical properties under different conditions were studied systematically. Under a cyclic force of 0.05 N (peak value), a peak voltage of 91.23 V, maximum power of 4.16 mW were measured at 60 Hz with a proof mass of 0.5 g. The results demonstrate the potential of the device in energy harvesting applied to low-power portable electronics and wireless sensors.
Applied Physics Letters 02/2010; 96(8):083502-083502-3. · 3.84 Impact Factor
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ABSTRACT: We investigated the dielectric, ferroelectric, and pyroelectric properties of Mn-doped 0.74 Pb ( Mg <sub>1/3</sub> Nb <sub>2/3</sub>) O <sub>3</sub>–0.26 PbTiO <sub>3</sub> crystals. Compared with pure PMN-0.26PT, Mn substitutions resulted in reduced dielectric loss and enhanced coercive field. Furthermore, the pyroelectric coefficient and detectivity figures of merits were enhanced to 17.2×10<sup>-4</sup> C / m <sup>2</sup> K and 40.2×10<sup>-5</sup> Pa <sup>-1/2</sup> , respectively, which were the highest values so far reported among intrinsic pyroelectric materials with rhombohedral-tetragonal phase transition temperature greater than 90 ° C . The specific detectivity of infrared detector based on Mn-doped crystals was 1.07×10<sup>9</sup> cm Hz <sup>1/2</sup> W <sup>-1</sup> , and approximately doubles that of commercial LiTaO <sub>3</sub> crystals-based, which makes them promising candidates for infrared detectors applications.
Applied Physics Letters 12/2009; · 3.84 Impact Factor
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ABSTRACT: The phase transitions of as-grown (1-x)PbMg(1/3)Nb(2/3)O(3)-xPbTiO(3) (PMN-xPT) crystals with PT compositions of x = 0.31 and 0.38 under a dc electric field were observed in a polarization microscope. The optical transmissions of the crystals under dc electric fields were measured in the wavelength region around their optical absorption edges. The band gaps of the orthorhombic and tetragonal phases under the applied electric field were obtained. By combining both of the optical methods, the phase transition from the tetragonal to the orthorhombic phase was observed in PMN-0.38PT crystals when the electric field along the [110](cub) direction reaches up to 300 V mm(-1). Whereas the PMN-0.31PT crystals undergo the pseudo-phase-transition under a dc electric field along the [110](cub) direction. The pseudo-phase-transition possibly stems from the reorientation and growth of microdomains in PMN-0.31PT crystals.
Journal of Physics Condensed Matter 08/2009; 21(33):335902. · 2.55 Impact Factor
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ABSTRACT: The phase transitions of as-grown (1−x)PbMg1/3Nb2/3O3–xPbTiO3 (PMN–xPT) crystals with PT compositions of x = 0.31 and 0.38 under a dc electric field were observed in a polarization microscope. The optical transmissions of the crystals under dc electric fields were measured in the wavelength region around their optical absorption edges. The band gaps of the orthorhombic and tetragonal phases under the applied electric field were obtained. By combining both of the optical methods, the phase transition from the tetragonal to the orthorhombic phase was observed in PMN–0.38PT crystals when the electric field along the [110]cub direction reaches up to 300 V mm−1. Whereas the PMN–0.31PT crystals undergo the pseudo-phase-transition under a dc electric field along the [110]cub direction. The pseudo-phase-transition possibly stems from the reorientation and growth of microdomains in PMN–0.31PT crystals.
Journal of Physics Condensed Matter 07/2009; 21(33):335902. · 2.55 Impact Factor
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ABSTRACT: Long range correlation dynamics of polarization clusters in BaTiO3 have been observed directly near the Curie temperature (TC) by photon correlation spectroscopy. A correlation length on the order of 200 nm was found to be dynamic near TC with a characteristic relaxation time of several microseconds. This relaxation time decreased with an increase in temperature, but exhibited an anomaly at TC, indicating the dominating contribution to the dielectric permittivity by these polarization clusters near TC.
Applied Physics Letters 11/2008; 93(19):192908-192908-3. · 3.84 Impact Factor
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Wenwei Ge,
Hong Liu,
Xiangyong Zhao,
Bijun Fang, Xiaobing Li,
Feifei Wang,
Dan Zhou,
Ping Yu,
Xiaoming Pan,
Di Lin,
Haosu Luo
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ABSTRACT: A large single crystal of 0.95Na0.5Bi0.5TiO3–0.05BaTiO3 (0.95NBT–0.05BT) with dimensions of 35 mm diameter × 10 mm length was grown by the top-seeded-solution growth method (TSSG). X-ray powder diffraction results indicate that the as-grown 0.95NBT–0.05BT crystal is of a perovskite structure and belongs to the rhombohedral system. The dielectric, ferroelectric and piezoelectric properties were investigated in detail. The room temperature dielectric constants for unpoled 0 0 1, 1 1 0 and 1 1 1 oriented crystal samples are 1450, 1650 and 1750 at 1 kHz and decrease to 1050, 800 and 480 after poling. The remanent polarizations Pr of 0 0 1, 1 1 0 and 1 1 1 oriented crystal samples are 16.44 µC cm−2, 23.69 µC cm−2 and 27.63 µC cm−2 with the coercive fields Ec of 32.72 kV cm−1, 31.20 kV cm−1 and 28.15 kV cm−1, respectively. Interestingly, the piezoelectric constant d33 of the 0.95NBT–0.05BT crystal shows apparent anisotropy along its pseudocubic 0 0 1, 1 1 0 and 1 1 1 directions. The 0 0 1 poled 0.95NBT–0.05BT crystals show excellent piezoelectric properties with d33 = 280 pC N−1. However, the d33 values of the 1 1 1 oriented 0.95NBT–0.05BT crystal are only 90 pC N−1. The origin of apparent anisotropy in piezoelectric properties has been discussed in detail.
Journal of Physics D Applied Physics 05/2008; 41(11):115403. · 2.54 Impact Factor
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ABSTRACT: The method to distinguish two types of monoclinic phases (MA and MB) in perovskite crystals by polarized light microscopy was developed. The MA-type monoclinic phase was observed in xPb(In1/2Nb1/2)O3–yPb(Mg1/3Nb2/3)O3–zPbTiO3 ternary crystal by polarized light microscopy at room temperature. The phase transition of these monoclinic phases under dc electric field along [1 1 0]cub direction was investigated in real time. Two dielectric peaks were found in ferroelectric phases of the as-grown ternary single crystals near the morphotropic phase boundary (MPB) with increasing temperature, which indicate the phase transition of monoclinic MA → orthorhombic (O) → tetragonal (T).
Materials Chemistry and Physics 122:350-353. · 2.23 Impact Factor
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ABSTRACT: Relaxor-based ferroelectric single crystals Mn doped 0.72Pb(Mg1/3Nb2/3)O3–0.28PbTiO3 (Mn–PMN–0.28PT) were grown by the modified Bridgman technique. The effects of nitrogen annealing on structural quality, defect and electrical properties of [1 1 1]-oriented Mn–PMN–0.28PT were systematically investigated. X-ray rocking curves (XRC) were used and the results indicated that the quality of single crystals could be significantly improved by appropriate annealing. X-ray photoelectron spectroscopy (XPS) was used to investigate the content and valence states of main elements in Mn–PMN–0.28PT, including oxygen vacancies. The conduction mechanisms at different temperature ranges were discussed. The dielectric loss of annealed samples decreased about 50% compared to the unannealed one, which should be attributed to the motion of domain walls pinned by defects. The pinning effect caused by oxygen vacancies on domain wall motion was enhanced through nitrogen annealing and the pyroelectric performances were optimized.
Journal of Crystal Growth 318(1):865-869. · 1.73 Impact Factor
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ABSTRACT: A ternary relaxor ferroelectric single crystal Pb(In1/2Nb1/2)O3–Pb(Mg1/3Nb2/3)O3–PbTiO3 was grown by the modified Bridgman method. The real compositions, phase structures and performances of different regions in the boule were characterized. The real composition deviated from the nominal composition, but the In/Pb ratio in the crystal remained nearly a constant. The piezoelectric coefficient d33, electromechanical coupling factor k33 and coercive field Ec after 〈0 1 1〉 poling can reach up to 1500 pC/N, 0.90 and 4 kV/cm, respectively. More importantly, the rhombohedral to tetragonal phase transition temperature (Trt) in PIN–PMN–PT single crystal with rhombohedral composition increased to 114 °C, which made the ternary system single crystal fit for the applications in wider temperature range.
Journal of Crystal Growth 318(1):890-894. · 1.73 Impact Factor
