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Showing 1 to 12 of 12 for “"relaxor ferroelectrics"”.
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Dielectric noise spectroscopy of relaxor ferroelectrics
… answer one simple question: are the dynamics of relaxor ferroelectrics cooperative? To accomplish this task, we have developed a promising new technique that is excellent at sorting out the internal dynamics of high dielectric materials. Specifically we have examined the dynamics of the relaxor …
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Aging and Barkhausen noise in the relaxor ferroelectrics
"Relaxor ferroelectrics are disordered crystalline materials whose polar order is limited to mesoscopic-scaled nanodomains. There is no ferroelectric phase transition, but a faster than Arrhenius cooperative freezing into a glassy relaxor regime instead. It is not understood how the random fields …
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Structure-property relationships in strontium barium niobate relaxor ferroelectrics
… response found for Pb-based perovskite relaxors. The dielectric absorption of SBN was also found to be much stronger along the c-axis than along any other orientation. Investigations of the temperature dependence of the high-field polarization behavior found that a square-to-slim loop …
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Development of phonon-polarization THz spectroscopy, and the investigation of relaxor ferroelectrics
… first THz frequency dielectric measurements of a relaxor ferroelectric crystal, in particular KTao0.982Nb0.018O3 (KTN 1.8). THz spectroscopy has emerged as an important probe for a wide variety of systems with the development of pulsed THz radiation sources and time-domain detection methods. Four …
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Synchrotron X -Ray Scattering Studies of Local Fluctuations in Lead Magnesium Niobate Relaxor Ferroelectrics
Temperature dependent synchrotron x-ray diffraction studies of PMN-PT single crystals confirmed the existence of anti-ferroelectric fluctuations produced by correlated atomic displacements using state-of-the art experimental facilities. Detailed quantitative analysis of the corresponding …
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The Freezing Mechanisms of Perovskite Relaxor Ferroelectrics and the Thermodynamic Stability of their Ferroelectric States
Relaxor ferroelectrics are disordered crystalline materials that have short-range ferroelectric order, known as polar nanoregions. These materials do not exhibit a ferroelectric phase transition at zero field, but rather enter a glassy-like relaxor regime. The source of the glassy freezing and the …
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Temperature And Pressure Effects On Elastic Properties Of Relaxor Ferroelectrics And Thermoelectrics: A Resonant Ultrasound Spectroscopy Study
Relaxor ferroelectric lead magnesium niobate-lead titanate (PMN-PT) material exhibits exceptional electromechanical properties. The material undergoes a series of structural phase transitions with changes in temperature and the chemical composition. The work covered in this dissertation seek to …
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Microstructure and Electrical Properties of Mocvd-Derived Perovskite Lead Zirconium(x) Titanium(1-X) Oxygen(3) and Lead (Scandium Tantalum)(1-X) Titanium(x) Oxygen(3) Thin Films on Lanthanum Nickel Oxide Electrode-Buffered Silicon
… PZT thin films, we expanded the work to grow relaxor ferroelectric thin films. Solid solutions of Pb(Sc1/2Ta1/2)1-xTixO 3 (x = 0--0.3) (PSTT) were grown. Phase evolution of the PSTT thin films with respect to the growth conditions, including growth temperature, processing of the bottom …
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Experimental investigation and modeling of the electrostrictive relaxor ferroelectric lead magnesium niobate-lead titinate
… behaviors of the electrostrictive relaxor ferroelectric lead magnesium niobate-lead titinate (PMN-PT) are experimentally characterized and phenomenologically modeled. The dependencies of PMN-PT electromechanical transduction on temperature and frequency, characteristics of relaxor …
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Structure-property correlations in compositionally complex ferroelectrics
… to the emergence of unconventional behavior. Ferroelectrics with switchable polar ordering, for instance, are influenced by local compositional variation, thus requiring an understanding of structure-property relationships. My dissertation work focuses on using atomic scale characterization …
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Dynamic Properties of Materials: Phonons from Neutron Scattering
… with technologically important materials -- relaxor ferroelectrics and high temperature pnictide superconductors. The conclusions draw together the different strands of the work, discussing the importance of these new advances together with future developments and scientific applications.
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Determination of local crystal symmetry in complex, multielement, ferroelectric perovskites and alloys
… in complex oxides, polarization nanodomains in ferroelectrics, and vortex matter. A common scheme to these systems is that there exists a distinction between local crystal symmetry and the average, macroscopic symmetry imposed by fluctuations in the crystal lattice. Before we can control and …