Domain Structures and Phase Transitions in Barium Titanate

1949 ◽  
Vol 76 (8) ◽  
pp. 1187-1201 ◽  
Author(s):  
P. W. Forsbergh
Keyword(s):  
Phase Transitions ◽  
Barium Titanate ◽  
Domain Structures

Crystal-chemical aspects of phase transitions in barium titanate

2003 ◽  
Vol 127 (8) ◽  
pp. 557-562 ◽  
Author(s):  
Katarzyna Tkacz-Śmiech ◽  
Andrzej Koleżyński ◽  
W.S. Ptak
Keyword(s):  
Phase Transitions ◽  
Barium Titanate ◽  
Crystal Chemical

Grain-Size Effects on Diffuse Phase Transitions of Batio3 Ceramics Obtained by Alkoxide Precursors

1994 ◽  
Vol 346 ◽  
Author(s):  
R. P. S. M. Lobo ◽  
R. L. Moreira ◽  
N. D. S. Mohallem
Keyword(s):  
Grain Size ◽  
Phase Transitions ◽  
Barium Titanate ◽  
Size Effects ◽  
Sol Gel ◽  
Simple Relationship ◽  
Titanate Ceramics ◽  
Charged Defects ◽  
Alkoxide Precursors ◽  
Diffuse Phase

ABSTRACTBarium titanate ceramics have been obtained by sol-gel methods. The dielectric investigations of these materials revealed the existence of diffuse ferroelectric transitions. By using a phenomenological model, we could demonstrate the existence of a simple relationship between the diffuse character of the transition and the sample grain-size. This effect has been attributed to interactions between charged defects on the grain surfaces and the spontaneous polarization of the material.

Ferroelastic phase transitions and domain structures in powders

2005 ◽  
Vol 220 (8) ◽  
Author(s):  
Hans Boysen
Keyword(s):  
Phase Transitions ◽  
Domain Walls ◽  
Approximate Model ◽  
Second Phase ◽  
High Symmetry ◽  
Line Profiles ◽  
Line Broadening ◽  
Rietveld Refinements ◽  
Domain Structures ◽  
Individual Line

AbstractPowder patterns of samples resulting from ferroelastic phase transitions generally show typical line profiles: asymmetry into the direction of the position of the corresponding hypothetical high symmetry reflection and strongly anisotropic line broadening. An approximate model is presented that describes the characteristic distribution of individual line widths based on the variation of lattice spacings within the domain walls. The variation with temperature is governed by the competition of decreasing spontaneous strain and increasing wall widths and/or wall densities. It is argued that conventional Rietveld refinements can easily lead to erroneous results and a simplified method is proposed to approximate the actual line profiles via the introduction of a second phase with anisotropic strain broadening to take into account the scattering fom the domain walls.

Growth of KNbO3 Crystal by a Pulling down Method

2011 ◽  
Vol 284-286 ◽  
pp. 2307-2310
Author(s):  
Min Jin ◽  
Hui Shen ◽  
Jia Yue Xu
Keyword(s):  
Phase Transitions ◽  
Room Temperature ◽  
Cone Angle ◽  
Xrd Analysis ◽  
Complex Domain ◽  
Blue Color ◽  
Domain Structures

In the present work, a pulling down method was introduced to prepare the KNbO3 crystals and the growth results were evaluated. It was found the Pt crucible with 60° cone angle and folds at the seed well was helpful to obtain KNbO3 crystal with nice integrity. The blue color occurred on the top of KNbO3 ingot was confirmed to be orthorhombic KNbO3 by XRD analysis. Some complex domain structures, including 60°, 90° and 180° domains, were happened in the crystal which were attributed to phase transitions when it was cooled down to room temperature.

Effect of Grain Size on Phase Transitions and Dielectric Properties of Nano-Crystalline Barium Titanate Ceramics

2012 ◽  
Vol 602-604 ◽  
pp. 192-196
Author(s):  
Li Ming Wang ◽  
Xiang Yun Deng ◽  
Hai Tao Zhang ◽  
Jian Bao Li ◽  
Di Chen ◽  
...  
Keyword(s):  
Phase Transition ◽  
Grain Size ◽  
Phase Transitions ◽  
Barium Titanate ◽  
Fine Grain ◽  
Nano Crystalline ◽  
Plasma Sintering ◽  
Transmission Electron ◽  
Spark Plasma ◽  
Titanate Ceramics

Barium titanate (BaTiO3) ceramics with grain size varied from 1000 to 8 nm were prepared by two step sintering method (TSS) and spark plasma sintering (SPS), respectively. Mixture structures of BaTiO3 ceramics were proved by in-situ temperature high resolution x-ray diffraction. Multiple ferroelectric domains present in nano-crystalline BaTiO3 ceramics were observed by transmission electron microscope. The evolution of phase transitions supported the existence of intrinsic mechanism. Dielectric loss of fine grain size BaTiO3 was higher than coarse grain size during Curie phase transition due to diffuse phase transition and grain boundary effects.

scholarly journals Dielectric investigations of La-doped barium titanate

2010 ◽  
Vol 4 (3) ◽  
pp. 193-198 ◽  
Author(s):  
Tadas Ramoska ◽  
Juras Banys ◽  
Ricardas Sobiestianskas ◽  
Mirjana Vijatovic-Petrovic ◽  
Jelena Bobic ◽  
...  
Keyword(s):  
Phase Transitions ◽  
Barium Titanate ◽  
High Frequency ◽  
Low Frequency ◽  
High Temperature Phase ◽  
Temperature Phase ◽  
Relaxational Process ◽  
Pechini Process ◽  
La Doped ◽  
Curie Temperature Tc

In the present paper results of the dielectric investigation of barium titanate (BaTiO3) doped with different concentrations of lanthanum are presented. Ceramic samples were prepared by the Pechini process. With increased doping the grain size of ceramics decreases from 2.5 ?m in pure samples down to 0.2 ?m in 0.5 mol% La - doped BaTiO3. Ceramics showed maximally enhanced dielectric permittivity around low-, room and high temperature phase transitions, which are the phase transitions of the pure BaTiO3. The Curie temperature, TC, is lowered by 30 K with increase of doping concentration to 0.5 mol% La. Dielectric spectra revealed three parts: low frequency part which is caused by conductivity process, middle frequency relaxational process part and high frequency relaxational/polar modes contribution.

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