نتایج جستجو برای: pbtio3
تعداد نتایج: 687 فیلتر نتایج به سال:
We have investigated the interaction of oxygen vacancies and 180° domain walls in tetragonal PbTiO3 using density-functional theory. Our calculations indicate that the vacancies do have a lower formation energy in the domain wall than in the bulk, thereby confirming the tendency of these defects to migrate to, and pin, the domain walls. The pinning energies are reported for each of the three po...
We show that light drives large-amplitude structural changes in thin films of the prototypical ferroelectric PbTiO3 via direct coupling to its intrinsic photovoltaic response. Using time-resolved x-ray scattering to visualize atomic displacements on femtosecond time scales, photoinduced changes in the unit-cell tetragonality are observed. These are driven by the motion of photogenerated free ch...
Quantum mechanical simulation is an invaluable tool for studying material properties and behaviors due to its versatility and ability to probe properties not easily accessible in experiments. Employing the computational power of high performance HPCMP supercomputers, we investigated the oxidation states of ions in insulating solids, the stabilization of highly-polar PbTiO3 films, and defects in...
We use a near-field scanning microwave microscope to simultaneously image the dielectric constant, loss tangent, and topography in a PbTiO3 crystal. By this method, we study the effects of the local dielectric constant and loss tangent in the geometry of periodic domains on the measured resonant frequency, and quality factor. We also carry out theoretical calculations and the results agree well...
Relaxor-based ferroelectric single crystals Pb(Mg1/3Nb2/3)O3-PbTiO3 (PMN-PT) have drawn much attention in the ferroelectric field because of their excellent piezoelectric properties and high electromechanical coupling coefficients (d33~2000 pC/N, kt~60%) near the morphotropic phase boundary (MPB). Ternary Pb(In1/2Nb1/2)O3-Pb(Mg1/3Nb2/3)O3-PbTiO3 (PIN-PMN-PT) single crystals also possess outstan...
Composite materials comprised of ferroelectric nanoparticles in a dielectric matrix are being actively investigated for a variety of functional properties attractive for a wide range of novel electronic and energy harvesting devices. However, the dependence of these functionalities on shapes, sizes, orientation and mutual arrangement of ferroelectric particles is currently not fully understood....
In recent years, methods have been developed that allow first-principles electronic-structure calculations to be carried out under conditions of fixed electric field. For some purposes, however, it is more convenient to work at fixed electric displacement field. Initial implementations of the fixed-displacement-field approach have been limited to constraining the field along one spatial dimensi...
Submitted for the MAR11 Meeting of The American Physical Society All-atom effective models for first-principles simulations of the temperature-dependent behavior of complex ferroelectric oxides1 JORGE INIGUEZ, JACEK C. WOJDEL, ICMAB-CSIC, PATRICK HERMET, PHILIPPE GHOSEZ, University of Liege, ZEILA ZANOLLI, ICMAB-CSIC and University of Liege — Since its introduction in the 90’s, the first-princi...
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