Browsing by Author "Li, ZR"

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    In-situ neutron diffraction study of Pb(In1/2Nb1/2)O3-Pb(Mg1/3Nb2/3)O3-PbTiO3 single crystals under uniaxial mechanical stress
    (American Institute of Physics, 2012-04-26) Li, Q; Liu, Y; Luzin, V; Studer, AJ; Wan, YH; Li, ZR; Norén, L; Withers, RL; Xu, Z
    In this paper, we report the phase transition behavior of ternary relaxor ferroelectric single crystals of 0.25Pb(In1/2Nb1/2)O-3-0.44Pb(Mg1/3Nb2/3)O-3-0.31PbTiO(3) subject to a uniaxial mechanical stress up to 400 MPa. The resultant in situ neutron diffraction data are interpreted in terms of the polarization rotation theory and provide direct structural evidence for the stress-induced polarization rotation pathway deduced from studies of macroscopic physical properties under stress. It is suggested that an intermediate, metastable orthorhombic phase is induced above a critical pressure of similar to 75 MPa. This critical stress level appears to be unaffected by sample poling although the ground states (at zero stress) for the poled and unpoled crystals are different. The critical stress level, however, does decrease with increasing temperature. The elastic behavior of the intermediate phases is also studied based on a calculation of the associated lattice strains. (C) 2012 American Institute of Physics.
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    Structural transitions in [001]/[111]-oriented 0.26Pb(In1/2Nb1/2)O3-0.46Pb(Mg1/3Nb2/3)O3-0.28PbTiO3 single crystals probed via neutron diffraction and electrical characterization
    (AIP Publishing LLC, 2013-04-19) Li, Q; Liu, Y; Wang, J; Studer, AJ; Withers, RL; Li, ZR; Xu, Z
    We report changes in the metric symmetry of unpoled and electrically poled single crystals of 0.26Pb(In1/2 Nb 1/2)O3-0.46Pb(Mg1/3 Nb 2/3)O3-0.28PbTiO3, as revealed by neutron diffraction in conjunction with electrical measurements. The unpoled crystals show relaxor characteristics and an average rhombohedral symmetry that persists from ambient temperature up to the Curie temperature of ∼165 °C. Poling along a [111] direction enhances the rhombohedral distortion away from cubic metric symmetry but appears not to induce any monoclinic phases. By contrast, the poled [001]-oriented crystal has orthorhombic (or monoclinic MC ) metric symmetry at 25 °C. An intermediate transition to a metrically tetragonal phase around 120 °C is confirmed for both poled crystals. © 2013, AIP Publishing LLC.
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    Temperature dependence of electrical properties and crystal structure of 0.29Pb(In1/2Nb1/2)O-3-0.44Pb(Mg1/3Nb2/3)O-3-0.27PbTiO(3) single crystals
    (Hindawi Publishing Corporation, 2013-10-07) Li, Q; Liu, Y; Studer, AJ; Li, ZR; Withers, RL; Xu, Z
    We characterized the temperature dependent ( ∼ 25–200°C) electromechanical properties and crystal structure of Pb(In1/2Nb1/2)O3-Pb(Mg1/3Nb2/3)O3-PbTiO3 single crystals using in situ electrical measurement and neutron diffraction techniques. The results show that the poled crystal experiences an addition phase transition around 120°C whereas such a transition is absent in the unpoled crystal. It is also found that the polar order persists above the maximum dielectric permittivity temperature at which the crystal shows a well-defined antiferroelectric behavior. The changes in the electrical properties and underlying crystal structure are discussed in the paper. © 2013, Qian Li et al. This is an open access article distributed under the Creative Commons Attribution Licence