Phase-Dield Simulation of Rhombohedral and Tetragonal Phases in Ferroelectric Single Crystals

Aerospace ◽  
2006 ◽  
Author(s):  
T. Liu ◽  
C. S. Lynch
Keyword(s):  
Free Energy ◽  
Phase Transformations ◽  
Single Crystals ◽  
Electric Fields ◽  
Tetragonal Phase ◽  
Ferroelectric Materials ◽  
Integration Scheme ◽  
Ferroelectric Crystal ◽  
Domain Structures ◽  
Tdgl Equation

Ferroelectric materials exhibit spontaneous polarization and domain structures below the Curie temperature. In this work the phase field approach has been used to simulate phase transformations and the formation of ferroelectric domain structures. The evolution of phases and domain structures was simulated in ferroelectric single crystals by solving the time dependent Ginzburg-Landau (TDGL) equation with polarization as the order parameter. In the TDGL equation the free energy of a ferroelectric crystal is written as a function of polarization and applied fields. Change of temperature as well as application of stress and electric fields leads to change of the free energy and evolution of phase states and domain structures. In this work the finite difference method was implemented for the spatial description of the polarization and the temporal evolution of polarization field was computed by solving the TDGL equation with an explicit time integration scheme. Cubic to tetragonal, cubic to rhombohedral and rhombohedral to tetragonal phase transformations were modeled, and the formation of domain structures was simulated. Field induced polarization switching and rhombohedral to tetragonal phase transition were simulated.

Domain Dynamics under Unipolar Electric Fields for BaTiO3 Single Crystals

2013 ◽  
Vol 582 ◽  
pp. 40-43
Author(s):  
Shotaro Ishikawa ◽  
Yuuki Kitanaka ◽  
Yuji Noguchi ◽  
Masaru Miyayama ◽  
Chikako Moriyoshi ◽  
...  
Keyword(s):  
Synchrotron Radiation ◽  
Single Crystals ◽  
Electric Fields ◽  
Direct Evidence ◽  
Reversible Change ◽  
X Ray ◽  
Domain Structures ◽  
Diffraction Patterns ◽  
Domain Dynamics

Domain structures and dynamics of BaTiO3 single crystals under in-situ electric fields along <110>c were investigated by using synchrotron radiation single-crystal X-ray diffractions. Diffraction patterns clearly show the presence of a 90 ° domain structure in the crystals poled along <110>c. The diffraction analysis provides direct evidence of a reversible change in the volume fractions of two kinds of the 90 o domains under unipolar in-situ electric fields. This reversible change in the domain structures under unipolar fields is suggested to originate from the interaction between spontaneous polarization and defect dipoles composed of acceptor and oxygen vacancy.

scholarly journals Phase fragility and mechatronic reliability for Pb(Mg1/3Nb2/3)O3–PbTiO3 ferroelectric single crystals — A review

2014 ◽  
Vol 04 (01) ◽  
pp. 1430001 ◽  
Author(s):  
F. Fang ◽  
W. Yang
Keyword(s):  
Fatigue Crack ◽  
Electric Field ◽  
Crack Propagation ◽  
Single Crystals ◽  
Fatigue Crack Propagation ◽  
Failure Modes ◽  
Ultrasonic Transducer ◽  
Underlying Mechanism ◽  
Ferroelectric Materials ◽  
Domain Structures

Single crystals of (1-x) Pb ( Mg 1/3 Nb 2/3) O 3–x PbTiO 3( PMN –x PT ) near their morphotropic phase boundaries (MPBs) are under extensive investigations for their extraordinary high dielectric and piezoelectric behavior. Applications of those single crystals facilitated the breakthrough in ultrasonic transducer materials and devices. Ferroelectric materials are known to be fragile which often leads to various reliability failures in applications involving electric loadings. In a mechanical sense, the failure modes concern the fracture under an intensive electric field, and the fatigue crack propagation under an alternating electric field. In an electrical sense, the failure is exhibited by degenerated hysteresis loop by shrinking the remnant polarization and expanding the coercive field. All these modes degrade the performance for ferroelectric devices. As a departure from the tetragonal (T) ferroelectric materials, exemplified by BaTiO 3 and Pb ( ZrTi ) O 3, the domain structures of PMN–PT around the MPB are versatile and intricate, depending sensitively on the composition variation, orientation and previous loading history. In this review, the attention is mainly focused on three aspects. First, the phase fragility and multiphase coexistence are presented for both [100]- and [101]-oriented PMN–PT single crystals. Second, investigations on electric field-induced fatigue crack propagation are described, along with the orientation effect on the crack propagation behavior. Third, the inverse effects of the phase transition and fatigue crack growth on the polarization behavior, or the interaction between the mechanical and electrical degradations will be elucidated. The review aims for better understanding the underlying mechanism for the ultrahigh performance of the PMN–PT single crystals, to bridge the studies of ferroelectric materials from the mechanical and electrical senses, as well as to evaluate the reliability of PMN–PT single crystals under device applications.

Giant power density produced by PIN–PMN–PT ferroelectric single crystals due to a pressure induced polar-to-nonpolar phase transformation

2021 ◽  
Author(s):  
Sergey I. Shkuratov ◽  
Jason Baird ◽  
Vladimir G. Antipov ◽  
Christopher S. Lynch ◽  
Shujun Zhang ◽  
...  
Keyword(s):  
Phase Transformation ◽  
Energy Storage ◽  
Single Crystals ◽  
Power Density ◽  
Ferroelectric Materials ◽  
Power Supplies ◽  
Energy Storage Devices ◽  
Storage Devices ◽  
New Generation ◽  
Power Densities

The search for ferroelectric materials capable of producing high electric charge and power densities is important for developing a new generation of ultrahigh-power-density ferroelectric energy storage devices and autonomous megawatt power supplies.

scholarly journals Internal melt figures in ice by rapid adiabatic compression

1994 ◽  
Vol 40 (134) ◽  
pp. 132-134
Author(s):  
R.E. Gagnon ◽  
C. Tulk ◽  
H. Kiefte
Keyword(s):  
Phase Transformations ◽  
Grain Boundaries ◽  
Single Crystals ◽  
Adiabatic Compression ◽  
Air Bubbles ◽  
Water Ice ◽  
Deep Focus ◽  
And Behavior ◽  
First Time

AbstractSingle crystals and bicrystals of water ice have been adiabatically pressurized to produce, and clearly illustrate, two types of internal melt figures: (1) dendritic figures that grow from nucleation imperfections on the specimen’s surface, or from air bubbles at grain boundaries, into the ice as pressure is elevated; and (2) compression melt fractures, flat liquid-filled disks, that nucleate at imperfections in the crystal and grow with the application of pressure eventually to sprout dendritic fingers at the periphery. The transparency of the ice permitted visualization of the growth and behavior of the figures, and this could be an important tool in understanding the role of phase transformations in deep-focus earthquakes. Correlation between figure size and pressure is noted for the first time.

Investigation of the domain structure and hierarchy in potassium–sodium niobate lead-free piezoelectric single crystals

RSC Advances ◽  
2016 ◽  
Vol 6 (54) ◽  
pp. 49060-49067 ◽  
Author(s):  
Micka Bah ◽  
Natalya Alyabyeva ◽  
Richard Retoux ◽  
Fabien Giovannelli ◽  
Mustapha Zaghrioui ◽  
...  
Keyword(s):  
Single Crystals ◽  
Domain Structure ◽  
Lead Free ◽  
Nanometer Scale ◽  
Sodium Niobate ◽  
Potassium Sodium Niobate ◽  
Length Scales ◽  
Potassium Sodium ◽  
Domain Structures ◽  
Self Organized

We reported self-organized and hierarchized domain structures on various length scales ranging from micrometer to nanometer scale in K0.5Na0.5NbO3 crystals.

Pulsed laser-induced phase transformations in CdTe single crystals

2005 ◽  
Vol 248 (1-4) ◽  
pp. 259-263 ◽  
Author(s):  
E. Gatskevich ◽  
G. Ivlev ◽  
P. Přikryl ◽  
R. Černý ◽  
V. Cháb ◽  
...  
Keyword(s):  
Phase Transformations ◽  
Single Crystals ◽  
Pulsed Laser

FERROELECTRICS IN ACOUSTOELECTRONICS

Akustika ◽  
2021 ◽  
pp. 217
Author(s):  
Tamara Patrusheva ◽  
Sergey Petrov ◽  
Ludmila Drozdova ◽  
Aleksandr Shashurin
Keyword(s):  
Dielectric Constant ◽  
Electric Fields ◽  
Piezoelectric Effect ◽  
Complex Oxide ◽  
Ferroelectric Materials ◽  
Oxide Materials ◽  
Ferroelectric Films ◽  
Synthesis Time ◽  
Resonance Effects ◽  
Materials Used

Аcoustoelectronics is one of the areas of acoustics, associated with the use of mechanical resonance effects and the piezoelectric effect, as well as the effect based on the interaction of electric fields with waves of acoustic stresses in a piezoelectric material. The main materials used in acoustoelectronics are ferroelectrics, which are mainly complex oxide materials. This article discusses the possibility of increasing the purity and homogeneity of ferroelectric materials, as well as softening the regimes of their synthesis using the solution extraction-pyrolytic method. It is shown that the synthesis temperatures of BaTiO3, SrTiO3, and Pb(Zr)TiO3 ferroelectric films are reduced to 550-600°C, and the synthesis time is down to 5-10 minutes. The dielectric constant and Curie temperature values correspond to the maximum characteristics for these materials. Thus, using the extraction-pyrolytic method we obtained suitable for use in acoustoelectronic technology ferroelectric films.

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