Study of LiNbO3 and LiTaO3 ferroelectric domain structures using high-resolution x-ray diffraction under application of external electric field

2009 ◽  
Vol 105 (2) ◽  
pp. 024112 ◽  
Author(s):  
D. V. Roshchupkin ◽  
D. V. Irzhak ◽  
V. V. Antipov
2021 ◽  
Vol 54 (5) ◽  
pp. 1317-1326
Author(s):  
Arsen Petrenko ◽  
Nataliya Novikova ◽  
Alexander Blagov ◽  
Anton Kulikov ◽  
Yury Pisarevskii ◽  
...  

The anisotropy of deformations in potassium acid phthalate crystals arising under the action of an external electric field up to 1 kV mm−1 applied along the [001] polar axis was studied using X-ray diffraction methods at room temperature. Electrical conductivity was measured and rocking curves for reflections 400, 070 and 004 were obtained by time-resolved X-ray diffractometry in Laue and Bragg geometries. Two saturation processes were observed from the time dependences of the electrical conductivity. A shift in the diffraction peaks and a change in their intensity were found, which indicated a deformation of the crystal structure. Rapid piezoelectric deformation and reversible relaxation-like deformation, kinetically similar to the electrical conductivity of a crystal, were revealed. The deformation depended on the polarity and strength of the applied field. The deformation was more noticeable in the [100] direction and was practically absent in the [001] direction of the applied field. X-ray diffraction analysis revealed a disordered arrangement of potassium atoms, i.e. additional positions and vacancies. The heights of potential barriers between the positions of K+ ions and the paths of their possible migration in the crystal structure of potassium acid phthalate were determined. The data obtained by time-resolved X-ray diffractometry and X-ray structure analysis, along with additional electrophysical measurements, allow the conclusion that the migration of charge carriers (potassium cations) leads to lateral deformation of the crystal structure of potassium phthalate in an external electric field.


2020 ◽  
Vol 1 (1) ◽  
Author(s):  
Yoshihiro Kuroiwa ◽  
Sangwook Kim ◽  
Ichiro Fujii ◽  
Shintaro Ueno ◽  
Yuki Nakahira ◽  
...  

Abstract A large piezoelectric response in ferroelectric ceramics is typically associated with extrinsic contributions from ferroelectric domain structures. However, such domain structures cannot be expected in systems with pseudo-cubic symmetry. In this study, we determine the mechanism of significant piezoelectricity and ferroelectricity in 0.3BaTiO3–0.1Bi(Mg1/2Ti1/2)O3–0.6BiFeO3 ceramic with a perovskite-type pseudo-cubic symmetry. Synchrotron radiation X-ray diffraction reveals that the Bi ions in this ceramic essentially prefer to be off-centered at six sites by approximately 0.4 Å, in the cubic <100> directions. A phase transition occurs at TC ~725 K. However, the crystal seems to present a cubic symmetry even at room temperature. The large piezoelectric response is caused by the combinational partial ordering of the off-centered Bi ions, adapted to any direction of the applied electric field to the ceramic grains. The proposed mechanism for the emergence of a high polarization in the above system will enable designing novel Pb-free ceramics by controlling the fluctuated and off-centered ions under an applied electric field.


2000 ◽  
Vol 655 ◽  
Author(s):  
Matt Poulsen ◽  
S. Adenwalla ◽  
Stephen Ducharme ◽  
V.M. Fridkin ◽  
S.P. Palto ◽  
...  

AbstractX-ray diffraction was used to probe the structural changes associated with the conversion of the paraelectric phase to the ferroelectric phase that results from the application of a large external electric field. The samples under study are ultrathin (150 to 250 Å) Langmuir-Blodgett films of the copolymer vinylidene fluoride (70%) with trifluoroethylene (30%) deposited on aluminum-coated silicon. Theta-2theta X-ray diffraction was used to measure the change in inter-layer spacing perpendicular to the film surface. Upon heating at zero external electric field, the crystalline films undergo a structural phase transition, at 100± 5°C, from the all-trans ferroelectric phase to the trans-gauche paraelectric phase. [1,2] Above the phase transition temperature, the non-polar paraelectric phase can be converted back to the polar ferroelectric phase, in a smooth continuous process, using a large external electric field (∼1 GV/m). For example, at 100° C the ferroelectric phase first appears above 0.2 GV/m and increases steadily in proportion while the paraelectric phase decreases until complete conversion to the ferroelectric phase is achieved at approximately 0.6 GV/m.


2006 ◽  
Vol 62 (a1) ◽  
pp. s171-s171
Author(s):  
S. Gorfman ◽  
O. Schmidt ◽  
M. Schmidt ◽  
H. Borrmann ◽  
Y. Grin ◽  
...  

1990 ◽  
Vol 210 ◽  
Author(s):  
Heinz Graafsma ◽  
Jarek Majewski ◽  
David Cahen ◽  
Philip Coppens

AbstractWe have determined the displacements of the ions and the changes in cell parameters which occur on application of an electric field to a crystal of AgGaS2, using a three-step modulation method. The shifts in Bragg angle of 14 reflections, due to a fieldof 2.6 x 106 V/m applied nearly parallel to [221], were used to refine the change in cell parameters. The resulting piezo-electric coefficients are d14=d25 =8.8 (0.9) 10-12 C/N and d36=7.6 (1.8) 10-12 C/N. This leads to a value of 4.8 (0.5) pC/Nfor the piezoelectric constant in the [221] direction which compares well with a value of 5-6 10-12 C/N determined by other methods. The ionic displacements were studied on a second sample, with E=2.6x 106 V/m in adirection parallel to [110]. Very small, but significant a and b directiondisplacements were observed for all atoms, whereas the displacements in the c direction were negligible as expected. Relative to the sulfur framework, the Ga ion displacement is considerably larger than that of the Ag ions.


1997 ◽  
Vol 53 (3) ◽  
pp. 565-567 ◽  
Author(s):  
H. Graafsma ◽  
G. W. J. C. Heunen ◽  
S. Dahaoui ◽  
A. El Haouzi ◽  
N. K. Hansen ◽  
...  

The d 33 piezoelectric constant of KTiOPO4 (potassium titanium orthophosphate, KTP) has been determined for two different samples and at temperatures between 100 and 220 K, using high-resolution X-ray diffraction of a single-crystal in an electric field. The observed value of 15 (2) \times 10−12 m V−1 is between the two values of 10.4 and 25.8 \times 10−12 m V−1 found in the literature. The value of d 33 is shown to be constant over the temperature range 100–220 K and no anomaly was observed at the conductor–insulator transition at 150 K. The results obtained are believed to be sample-independent, since the same value was obtained for two different crystals, measured at different sources.


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