The Experts below are selected from a list of 11754 Experts worldwide ranked by ideXlab platform
Wenwu Cao - One of the best experts on this subject based on the ideXlab platform.
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temperature dependence of full set tensor properties of ktiopo4 single Crystal measured from one sample
2016Co-Authors: Yang Zhang, Liguo Tang, Gang Liu, Jiyang Wang, Huaidong Jiang, Wenwu CaoAbstract:The temperature dependence of the complete set of elastic, dielectric, and Piezoelectric constants of KTiOPO4 single Crystal has been measured from 20 °C to 150 °C. All 17 independent constants for the mm2 symmetry Piezoelectric Crystal were measured from one sample using extended resonance ultrasound spectroscopy (RUS), which guaranteed the self-consistency of the matrix data. The unique characteristics of the RUS method allowed the accomplishment of such a challenging task, which could not be done by any other existing methods. It was found that the elastic constants ( c11E, c13E, c22E, and c33E) and Piezoelectric constants ( d15, d24, and d32) strongly depend on temperature, while other constants are only weakly temperature dependent in this temperature range. These as-grown single domain data allowed us to calculate the orientation dependence of elastic, dielectric, and Piezoelectric properties of KTiOPO4, which are useful for finding the optimum cut for particular applications.
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tunable passband in one dimensional phononic Crystal containing a Piezoelectric 0 62pb mg1 3nb2 3 o3 0 38pbtio3 single Crystal defect layer
2014Co-Authors: Yuling Wang, Wenwu Cao, Wei Song, Enwei Sun, Rui ZhangAbstract:Longitudinal acoustic wave propagation in one-dimensional phononic Crystal containing a 0.2 mol% Fe-doped relaxor-based ferroelectric 0.62Pb(Mg1/3Nb2/3)O3–0.38PbTiO3 (PMN–0.38PT) single Crystal defect layer is theoretically studied using the transfer matrix method. A passband can be produced in the stopband when the inserted PMN–0.38PT layer with thickness around its half wavelength. The frequency of the passband is closely dependent on the PMN–PT strain coefficient, suggesting that the band structure of phononic Crystal is tunable by applying external electric field onto the Piezoelectric Crystal. Also, we investigated the influence of acoustic impedance of periodic constitutive materials (layers A and B) on the passband, where the bandwidth of the new passband becomes narrower as the acoustic impedance ratio of layer A and B (ZA/ZB) increase. The simulated results provide valuable guidance for designing tunable acoustic filters and switches made of phononic Crystal consisting of the Piezoelectric defect layer.
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large size lead free na k nb ta o3 Piezoelectric single Crystal growth and full tensor properties
2013Co-Authors: Limei Zheng, Xiaoqing Huo, Rui Wang, Junjun Wang, Wenhua Jiang, Wenwu CaoAbstract:Environmental friendly Piezoelectric single Crystal, Ta-modified (K,Na)NbO3 with the size of 12 × 11 × 11 mm3, has been successfully grown using the top seeded solution growth technique. This orthorhombic phase (K,Na)(Nb,Ta)O3 single Crystal is the largest size to date in KNN-based Crystals with homogeneous composition. The large size allowed us to apply the domain engineering technique to further enhance its Piezoelectric properties. In addition, a self-consistent complete set of elastic, dielectric and Piezoelectric constants for the [001]c poled domain engineered Crystal has been measured, which is urgently needed for theoretical studies and simulation designs of electromechanical devices using this lead-free Piezoelectric material. The electromechanical coupling factors are very high (k33 = 0.827, kt = 0.646) and the dielectric loss tangent is as low as 0.004 for this lead-free Piezoelectric Crystal. Such excellent properties make this Crystal an excellent candidate to replace lead-containing Piezoelectric materials in electromechanical devices.
Yuichi Ikuhara - One of the best experts on this subject based on the ideXlab platform.
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real time direct observations of polarization reversal in a Piezoelectric Crystal pb mg1 3nb2 3 o3 pbtio3 studied via in situ electrical biasing transmission electron microscopy
2011Co-Authors: Yukio Sato, Tsukasa Hirayama, Yuichi IkuharaAbstract:The ultrahigh Piezoelectricity of lead magnesium niobate--lead titanate (PMN-PT) single Crystals is utilized for medical imaging and ultrasonic devices. It has been revealed that the domain structure is miniaturized down to the nanometer scale, indicating that the domain structure and its response to electric fields could play more roles. In this Letter, we report real-time direct observations of polarization reversals in PMN-PT with the use of in situ electrical biasing transmission electron microscopy. We find that a dominant behavior is a reversible response composed of the reorientation of nanoscale non-180\ifmmode^\circ\else\textdegree\fi{} domain walls (DWs) and movement and/or elimination of microscale DWs. These results basically agree with some predictions made by adaptive phase theory (Jin et al. [J. Appl. Phys. 94, 3629 (2003)]) which gives explanations of extrinsic contributions to the high Piezoelectricity of this material.
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real time direct observations of polarization reversal in a Piezoelectric Crystal pb mg 1 3 nb 2 3 o 3 pbtio 3 studied via in situ electrical biasing transmission electron microscopy
2011Co-Authors: Yukio Sato, Tsukasa Hirayama, Yuichi IkuharaAbstract:The ultrahigh Piezoelectricity of lead magnesium niobate\char21{}lead titanate (PMN-PT) single Crystals is utilized for medical imaging and ultrasonic devices. It has been revealed that the domain structure is miniaturized down to the nanometer scale, indicating that the domain structure and its response to electric fields could play more roles. In this Letter, we report real-time direct observations of polarization reversals in PMN-PT with the use of in situ electrical biasing transmission electron microscopy. We find that a dominant behavior is a reversible response composed of the reorientation of nanoscale non-180\ifmmode^\circ\else\textdegree\fi{} domain walls (DWs) and movement and/or elimination of microscale DWs. These results basically agree with some predictions made by adaptive phase theory (Jin et al. [J. Appl. Phys. 94, 3629 (2003)]) which gives explanations of extrinsic contributions to the high Piezoelectricity of this material.
P G Gowtham - One of the best experts on this subject based on the ideXlab platform.
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mechanical back action of a spin wave resonance in a magnetoelastic thin film on a surface acoustic wave
2016Co-Authors: P G Gowtham, Dominic Labanowski, Sayeef SalahuddinAbstract:Surface acoustic waves (SAWs) traveling on the surface of a Piezoelectric Crystal can, through the magnetoelastic interaction, excite traveling spin-wave resonance in a magnetic film deposited on the substrate. This spin-wave resonance in the magnetic film creates a time-dynamic surface stress of magnetoelastic origin that acts back on the surface of the Piezoelectric and modifies the SAW propagation. Unlike previous analyses that treat the excitation as a magnon-phonon polariton, here the magnetoelastic film is treated as a perturbation modifying boundary conditions on the SAW. We use acoustical perturbation theory to find closed-form expressions for the back-action surface stress and strain fields and the resultant SAW velocity shifts and attenuation. We demonstrate that the shear stress fields associated with this spin-wave back-action also generate effective surface currents on the Piezoelectric both in phase and out of phase with the driving SAW potential. Characterization of these surface currents and their applications in determination of the magnetoelastic coupling are discussed. The perturbative calculation is carried out explicitly to first order (a regime corresponding to many experimental situations of current interest) and we provide a sketch of the implications of the theory at higher order.
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traveling surface spin wave resonance spectroscopy using surface acoustic waves
2015Co-Authors: P G Gowtham, Takahiro Moriyama, D C Ralph, R A BuhrmanAbstract:Coherent gigahertz-frequency surface acoustic waves (SAWs) traveling on the surface of a Piezoelectric Crystal can, via the magnetoelastic interaction, resonantly excite traveling surface spin waves in an adjacent thin-film ferromagnet. These excited surface spin waves, traveling with a definite in-plane wave-vector q∥ enforced by the SAW, can be detected by measuring changes in the electro-acoustical transmission of a SAW delay line. Here, we provide a demonstration that such measurements constitute a precise and quantitative technique for spin-wave spectroscopy, providing a means to determine both isotropic and anisotropic contributions to the spin-wave dispersion and damping. We demonstrate the effectiveness of this spectroscopic technique by measuring the spin-wave properties of a Ni thin film for a large range of wave vectors, |q∥| = 2.5 × 104–8 × 104 cm−1, over which anisotropic dipolar interactions vary from being negligible to quite significant.
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traveling surface spin wave resonance spectroscopy using surface acoustic waves
2015Co-Authors: P G Gowtham, Takahiro Moriyama, D C Ralph, R A BuhrmanAbstract:Coherent gigahertz-frequency surface acoustic waves (SAWs) traveling on the surface of a Piezoelectric Crystal can, via the magnetoelastic interaction, resonantly excite traveling spin waves in an adjacent thin-film ferromagnet. These excited spin waves, traveling with a definite in-plane wave-vector q enforced by the SAW, can be detected by measuring changes in the electro-acoustical transmission of a SAW delay line. Here, we provide a first demonstration that such measurements constitute a precise and quantitative technique for spin-wave spectroscopy, providing a means to determine both isotropic and anisotropic contributions to the spin-wave dispersion and damping. We demonstrate the effectiveness of this spectroscopic technique by measuring the spin-wave properties of a Ni thin film for a large range of wave vectors,q = 2.5 x 10^4 - 8 x 10^4 cm^(-1), over which anisotropic dipolar interactions vary from being negligible to quite significant.
R A Buhrman - One of the best experts on this subject based on the ideXlab platform.
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traveling surface spin wave resonance spectroscopy using surface acoustic waves
2015Co-Authors: P G Gowtham, Takahiro Moriyama, D C Ralph, R A BuhrmanAbstract:Coherent gigahertz-frequency surface acoustic waves (SAWs) traveling on the surface of a Piezoelectric Crystal can, via the magnetoelastic interaction, resonantly excite traveling surface spin waves in an adjacent thin-film ferromagnet. These excited surface spin waves, traveling with a definite in-plane wave-vector q∥ enforced by the SAW, can be detected by measuring changes in the electro-acoustical transmission of a SAW delay line. Here, we provide a demonstration that such measurements constitute a precise and quantitative technique for spin-wave spectroscopy, providing a means to determine both isotropic and anisotropic contributions to the spin-wave dispersion and damping. We demonstrate the effectiveness of this spectroscopic technique by measuring the spin-wave properties of a Ni thin film for a large range of wave vectors, |q∥| = 2.5 × 104–8 × 104 cm−1, over which anisotropic dipolar interactions vary from being negligible to quite significant.
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traveling surface spin wave resonance spectroscopy using surface acoustic waves
2015Co-Authors: P G Gowtham, Takahiro Moriyama, D C Ralph, R A BuhrmanAbstract:Coherent gigahertz-frequency surface acoustic waves (SAWs) traveling on the surface of a Piezoelectric Crystal can, via the magnetoelastic interaction, resonantly excite traveling spin waves in an adjacent thin-film ferromagnet. These excited spin waves, traveling with a definite in-plane wave-vector q enforced by the SAW, can be detected by measuring changes in the electro-acoustical transmission of a SAW delay line. Here, we provide a first demonstration that such measurements constitute a precise and quantitative technique for spin-wave spectroscopy, providing a means to determine both isotropic and anisotropic contributions to the spin-wave dispersion and damping. We demonstrate the effectiveness of this spectroscopic technique by measuring the spin-wave properties of a Ni thin film for a large range of wave vectors,q = 2.5 x 10^4 - 8 x 10^4 cm^(-1), over which anisotropic dipolar interactions vary from being negligible to quite significant.
Xian Zhao - One of the best experts on this subject based on the ideXlab platform.
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structural stability and electro elastic property of ycob Crystal annealed in harsh environment
2018Co-Authors: Shiwei Tian, Feifei Chen, Xiufeng Cheng, Shujun Zhang, Lili Li, Fapeng Yu, Yanlu Li, Xiulan Duan, Zhengping Wang, Xian ZhaoAbstract:The YCa4O(BO3)3 (YCOB) Piezoelectric Crystal has been actively studied for high temperature sensor applications in the last few years. In this paper, the structure stability and electro-elastic properties of the YCOB Crystal annealed in a harsh environment (high temperatures of 600–1100 °C and a low atmospheric pressure of 2 × 10−5 atm for 24 h) were studied. The chemical bonding energy of the annealed YCOB Crystal was studied, with variations being less than 0.2 eV, showing the high stability of the electronic structure in the YCOB Crystal. The energies of vacancy formation (EVF) for Y, Ca, O, and B atoms were analyzed via first principles calculation. The O atoms were found to possess the lowest EVF value, being easier to escape (annealing in critical conditions) and compensate (thermal treatment at elevated temperatures in air) when compared to other atoms, thus leading to oxygen vacancy defects and a decrease in the chemical bonding strength after the annealing process. This is deemed to be the main factor dominating the electro-elastic property changes and their recovery behaviours.The YCa4O(BO3)3 (YCOB) Piezoelectric Crystal has been actively studied for high temperature sensor applications in the last few years. In this paper, the structure stability and electro-elastic properties of the YCOB Crystal annealed in a harsh environment (high temperatures of 600–1100 °C and a low atmospheric pressure of 2 × 10−5 atm for 24 h) were studied. The chemical bonding energy of the annealed YCOB Crystal was studied, with variations being less than 0.2 eV, showing the high stability of the electronic structure in the YCOB Crystal. The energies of vacancy formation (EVF) for Y, Ca, O, and B atoms were analyzed via first principles calculation. The O atoms were found to possess the lowest EVF value, being easier to escape (annealing in critical conditions) and compensate (thermal treatment at elevated temperatures in air) when compared to other atoms, thus leading to oxygen vacancy defects and a decrease in the chemical bonding strength after the annealing process. This is deemed to be the main f...
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single Crystal growth and temperature dependent behaviors of melilite type Piezoelectric Crystal ca2al2sio7
2018Co-Authors: Chao Jiang, Yong Long, Lingfeng Kong, Feifei Chen, Shiwei Tian, Lifeng Qin, Xiufeng Cheng, Xian ZhaoAbstract:Abstract High temperature Piezoelectric Crystals are desired for sensing at elevated temperatures. In this work, a large size (2 in.) and low cost Ca 2 Al 2 SiO 7 (CAS) Crystal was grown by using the Czochralski pulling method. Thermal expansion coefficients α 11 and α 33 were measured and found to be on the order of 5.70 × 10 −6 /°C and 10.12 × 10 −6 /°C, respectively. The electrical resistivities of the CAS Crystal along the X- and Z-directions at 700 °C were found to be 3 × 10 7 and 2 × 10 8 Ω·cm, respectively. The electro-elastic constants were evaluated by using the impedance and pulse-echo methods, where the Piezoelectric coefficients d 14 and d 36 were determined to be 6.7 and 2.8 pC/N at room temperature, respectively. Moreover, the temperature dependence of the electro-elastic properties of the CAS Crystal was investigated. The variation of elastic compliances was found to be d 11 ∗ (3.1 pC/N) was achieved for the (XY tl )45°/−55° Crystal cut, and the largest shear Piezoelectric d 26 ∗ (4.7 pC/N) was found for the (YX l )45° Crystal cut, nearly two times that of α-quartz.
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Thermal Expansion and Electro-Elastic Features of Ba2TiSi2O8 High Temperature Piezoelectric Crystal
2018Co-Authors: Chao Jiang, Feifei Chen, Shiwei Tian, Xiufeng Cheng, Shujun Zhang, Xian ZhaoAbstract:A high-quality Ba2TiSi2O8 (BTS) single Crystal was grown using the Czochralski (Cz) pulling method. The thermal expansion and electro-elastic properties of BTS Crystal were studied for high temperature sensor applications. The relative dielectric permittivities ε 11 T / ε 0 and ε 33 T / ε 0 were determined to be 16.3 and 11.8, while the Piezoelectric coefficients d15, d31, d33 were found to be 17.8, 2.9, and 4.0 pC/N, respectively. Temperature dependence of electro-elastic properties were investigated, where the variation of elastic compliance s 55 E (= s 44 E ) was found to be <6% over temperature range of 20–700 °C. Taking advantage of the anisotropic thermal expansion, linear thermal expansion comparable to insulating alumina ceramic was achieved over temperature range up to 650 °C. The optimum Crystal cut with large effective Piezoelectric coefficient (>8.5 pC/N) and linear thermal expansion coefficient (8.03 ppm/°C) achieved for BTS Crystal along the (47°, φ) direction (φ is arbitrary in 0–360°), together with its good temperature stability up to 650 °C, make BTS Crystal a promising candidate for high temperature Piezoelectric sensors
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bridgman growth and characterization of the structure ordered ctgs single Crystal
2014Co-Authors: Hewei Wang, Feifei Chen, Shuai Hou, Jie Zhan, Xian ZhaoAbstract:Structural ordered langasite-type Piezoelectric Crystal Ca 3 Ta G a 3 Si 2 O 14 (CTGS) possess excellent high temperature Piezoelectric properties. In this work, large size(25mm in diameter and 80mm in length)CTGS single Crystalswere grown by using the vertical Bridgman method. High resolution X-ray diffraction technique was applied to characterize the Crystal quality, where the as-grown CTGS Crystals were found to show low FWHM value, being on the order of 11 (-d 12 ) was found to increase with temperature with variation less than 30%, while the variation of the elastic compliance s 22 was obtained to be <10% over the test temperature range, similar to the CTGS Crystals grown by using Czochralski method. All these results indicated that Bridgman method is an alternative to Czochralski method for high quality CTGS Crystal growth.
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characterization of neodymium calcium oxyborate Piezoelectric Crystal with monoclinic phase
2010Co-Authors: Shujun Zhang, Xian Zhao, D R Yuan, Chunming Wang, Thomas R ShroutAbstract:Piezoelectric Crystals of neodymium calcium oxyborate, NdCa4O(BO3)3 (NdCOB), were grown by the Czochralski technique. The density was measured using the Archimedes method and found to be 3.63 g/cm3, in good agreement with the theoretical value. The thermal properties of NdCOB have been investigated, with the specific heat being on the order of 0.550 J/(g °C). The four thermal expansion coefficients were measured and found to be α11 = 8.12, α13 = 0.680, α22 = 5.96, and α33 = 10.3 (10−6/°C), respectively. The relative dielectric permittivities were determined to be e11T/e0 = 9.90, e22T/e0 = 15.5, e33T/e0 = 10.2, and e13T/e0 = −1.60, respectively, with corresponding low dielectric loss at 100 kHz, being on the order of <0.1%. The complete set of dielectric, elastic, and Piezoelectric constants for NdCOB single Crystals were determined by the resonance method and compared to other oxyborate Crystals ReCa4O(BO3)3 (Re = rare earth), where NdCOB exhibited relatively higher Piezoelectric properties with d13 = −4....