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Chen H.,Ningbo University | Liang Z.,Ningbo University | Luo L.,Ningbo University | Ke Y.,Ningbo University | And 4 more authors.
Journal of Alloys and Compounds | Year: 2012

According to the molar ratio of 0.25Pb(In 1/2Nb 1/2)O 3-0.44Pb(Mg 1/3Nb 2/3)O 3-0.31PbTiO 3, PIMNT polycrystalline material was prepared by using the two-step columbite precursor route. Using the polycrystalline material prepared by solid-state reaction, 55 mm in diameter PIMNT single crystals with [1 1 0] orientation had been grown successfully by the seeded vertical Bridgman process with the optimum conditions. The crystal wafers on the [0 0 1]-cut were fabricated from the crystal boules oriented by the rotating orientation XRD method. As-grown crystal exhibits a peculiar phase evolution from rhombohedral to tetragonal phase along the growth direction due to the composition segregation in the crystal growth. As for [0 0 1]-oriented wafers fabricated from rhombohedral phase region, the crystal wafers exhibit a piezoelectric coefficient d 33 of 1500-2100 pC/N, a dielectric permittivity ε of 4600-5800 and a dielectric loss tan δ of 0.5-1%. Compare to the binary crystal PMNT, the ternary crystal wafers possess a higher phase transition temperature T r-t of 100-120 °C, a higher Curie temperature T c of 160-195 °C and a larger coercive field E c of 4.2-5.0 kV/cm, which are favorable for the higher power ultrasonic devices with a wider working temperature range. © 2011 Elsevier B.V. Source


Yao S.,Nanjing University | Hu X.,Shandong University | Yan T.,Shandong University | Liu H.,Shandong University | And 3 more authors.
Journal of Applied Crystallography | Year: 2010

A near-stoichiometric lithium niobate single crystal has been grown by the Czochralski method in a hanging double crucible with a continuous powder supply system. Twins were found at one of the three characteristic growth ridges of the as-grown crystal. The twin structure was observed and analyzed by transmission synchrotron topography. The image shifts δX and δY in the transmission synchrotron topograph were calculated for the 3 2 and 0 22 reflections based on results from high-resolution X-ray diffractometry. It is confirmed that one of the {0112}m planes is the composition face of the twin and matrix crystals. The formation mechanism of these twins is discussed. © 2010 International Union of Crystallography. Printed in Singapore-all rights reserved. Source


Yan T.,Shandong University | Zheng F.,Shandong University | Yu Y.,Deqing Huaying Electronics Company | Qin S.,Shandong University | And 3 more authors.
Journal of Applied Crystallography | Year: 2011

Lithium tantalate (LiTaO3, LT) wafers of different colors were prepared through chemical reduction of regular congruent LT wafers. Samples with different colors corresponding to different annealing temperatures were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, and measurements of the Curie temperature and density. It was found that chemical reduction does not influence the basic LT structure. The Ta charge state change due to chemical reduction was found to be the main reason for the formation of black LT wafers. © 2011 International Union of Crystallography Printed in Singapore-all rights reserved. Source


Sun D.,Shandong University | Leng Y.,Shandong University | Sang Y.,Shandong University | Kang X.,Shandong University | And 6 more authors.
CrystEngComm | Year: 2013

Nd3+ and Mg2+ co-doped LiTaO3 (Nd:MgO:LT) crystal has great potential for applications in self-frequency doubling (SFD) lasers, and self-optical parametric oscillation (SOPO) infrared lasers. However, a related high performance laser device has not yet been realized. No reliable data on the basic physical properties of Nd:MgO:LT have been obtained, because of the lack of high quality Nd:MgO:LT crystals available due to the great difficulty in growing this crystal. In this paper, by optimizing the growth parameters and the thermal field by means of simulation, a high quality Nd 3+ and Mg2+ co-doped LiTaO3 crystal was grown by a modified Czochralski method. A comprehensive characterization of the crystal, including structure, composition, thermal properties, and CW laser performance, was performed. The experimental results indicate that Nd:MgO:LT is a monocrystal with strong anisotropic physical properties. The anisotropic thermal expansion was confirmed by observing the lattice parameter variation via temperature-dependent XRD analysis. Some important physical property data, such as thermal diffusivity, thermal conductivity and specific heat of the Nd:MgO:LT single crystal are reported for the first time, and should be of great utility for the application of this crystal. A CW laser output power of 3.58 W with an optical-to-optical conversion efficiency of 11.55, and a slope efficiency of 13.78%, was achieved with an incident pump power of 31 W, which is the highest laser output reported for this kind of crystal. It is demonstrated that single crystal Nd:MgO:LT will have important applications in SFD and SOPO lasers. © 2013 The Royal Society of Chemistry. Source


Sun D.-H.,Shandong University | Liu H.,Shandong University | Sang Y.-H.,Shandong University | Qin X.-Y.,Deqing Huaying Electronics Company | And 2 more authors.
Rengong Jingti Xuebao/Journal of Synthetic Crystals | Year: 2012

Pure and MgO-doped near stoichiometric LiNbO3 (SLN) crystals in diameter of 2-inch have been successfully grown by a new hanging crucible Czochralski technique. The crystal structure, thermal and optical properties were characterized systematically. Moreover, a new invented method of wet chemical synthesis for preparing the raw materials plays an important part in improving the compositional and optical homogeneity of MgO doped SLN crystal. Further measurements indicate the good uniformity of the sample and meet the corresponding application requirements very well. Source

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