Effect of Defects on Dielectric Properties in KTiOPO4, KTiOAsO4, RbTiOAsO4 and CsTiOAsO4 Single Crystals

1996 ◽  
Vol 453 ◽  
Author(s):  
A. R. Guo ◽  
Z. -Y. Cheng ◽  
R. S. Katiyar ◽  
Ruyan Guo ◽  
A. S. Bhalla
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Dielectric Relaxation ◽  
Relaxation Process ◽  
Single Crystals ◽  
Cage Structure ◽  
Dielectric Relaxation Process ◽  
Alkali Ions ◽  
Temperature Range ◽  
Temperature Relaxation

AbstractDielectric measurements were carried out in single crystals of KTiOPO4, KTiOAsO4, RbTiOAsO4 and CsTiOAsO4. All of the materials exhibit a clear dielectric relaxation process in the low temperature range and a conductance mechanism in the high temperature range. The dielectric relaxation process can be well described by the Debye dielectric model with an activation energies of 0.8 eV, 0.5 eV and 0.4 eV respectively. The relaxation process is associated with the deviation of the alkali ions from its ideal lattice positions. The high temperature conductance is associated with the motion of the alkali ions from one lattice site to another. Therefore, both the low temperature relaxation process and the high temperature conductance originate from different features of defect behavior of alkali ions in the cage structure of these materials.

High temperature dielectric relaxation anomalies in Ca0.9Nd0.1Ti0.9Al0.1O3−δ single crystals

RSC Advances ◽  
2015 ◽  
Vol 5 (96) ◽  
pp. 78414-78421 ◽  
Author(s):  
G. Murugesan ◽  
R. Nithya ◽  
S. Kalainathan ◽  
Shamima Hussain
Keyword(s):  
High Temperature ◽  
Dielectric Relaxation ◽  
Single Crystals ◽  
Room Temperature ◽  
Dielectric Studies ◽  
Floating Zone ◽  
Temperature Range

We herein report dielectric studies on Ca0.9Nd0.1Ti0.9Al0.1O3−δ single crystals grown by the optical floating zone technique in the temperature range from room temperature to 660 K.

Dielectric Relaxation Process and Pyroelectric Currents in LiNbO3 : Fe Single Crystals

1991 ◽  
Vol 125 (2) ◽  
pp. 723-729 ◽  
Author(s):  
P. C. Barbosa ◽  
J. A. C. de Paiva ◽  
J. Mendes Filho ◽  
A. C. Hernandes ◽  
J. P. Andreeta ◽  
...  
Keyword(s):  
Dielectric Relaxation ◽  
Relaxation Process ◽  
Single Crystals ◽  
Dielectric Relaxation Process

scholarly journals PVDF-HFP/NKBT composite dielectrics: Perovskite particles induce the appearance of an additional dielectric relaxation process in ferroelectric polymer matrix

2021 ◽  
Vol 96 ◽  
pp. 107093
Author(s):  
Vera P. Pavlović ◽  
Dragana Tošić ◽  
Radovan Dojčilović ◽  
Duško Dudić ◽  
Miroslav D. Dramićanin ◽  
...  
Keyword(s):  
Dielectric Relaxation ◽  
Relaxation Process ◽  
Polymer Matrix ◽  
Dielectric Relaxation Process ◽  
Ferroelectric Polymer

Structural-phase transition in (Cu2Te)2−x(ZnTe)x at high temperature

2021 ◽  
pp. 2150113
Author(s):  
H. B. Gasimov ◽  
R. M. Rzayev
Keyword(s):  
Phase Transition ◽  
Phase Transitions ◽  
High Temperature ◽  
Single Crystals ◽  
Structural Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Temperature Range ◽  
Xrd Study ◽  
Xrd Method

Cu2Te single crystal was grown by the Bridgman method. X-ray diffraction (XRD) study of Cu2Te single crystals in the temperature range of 293–893 K was performed and possible phase transitions in the mentioned range of temperature have been investigated. (Cu2Te)[Formula: see text](ZnTe)[Formula: see text] single crystals also were grown with [Formula: see text], 0.05, 0.10 concentrations and structural properties of the obtained single crystals were investigated by the XRD method in the temperature range 293–893 K. Lattice parameters and possible phase transitions in the mention temperature range were determined for (Cu2Te)[Formula: see text](ZnTe)[Formula: see text] single crystals for [Formula: see text], 0.05, 0.10 concentrations.

Basic Experiment on Lithium Removal Technique

2012 ◽  
Author(s):  
Tomohiro Furukawa ◽  
Yasushi Hirakawa
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Dissolution Rate ◽  
Chemical Reaction ◽  
Pure Water ◽  
Preliminary Investigation ◽  
Testing Temperature ◽  
Temperature Range ◽  
Removal Technique ◽  
Good Agreement

As a preliminary investigation into the establishment of a lithium removal technique for the components used at the International Fusion Materials Irradiation Facility (IFMIF), experiments were performed on the dissolution of lithium in three solvents: ethanol, pure water, and ethanol–water. In these experiments, hemispherical lithium was immersed in the solvents at constant temperatures, and the degree of dissolution was measured continuously from the height of the sample. From the obtained data, the average dissolution rate in the solvents at each testing temperature (10–90 °C) and the amount of hydrogen generated by the chemical reaction were calculated. The average dissolution rates in ethanol, pure water, and ethanol–water at 30 °C were 0.01, 1.6, and 0.43 mm/min, respectively. Although the average dissolution rate increased with the testing temperature in the low-temperature range (10–50 °C) for all solvents, this increase was saturated in the high-temperature range (50–90 °C) in experiments with pure water and ethanol–water as solvents. The volume of gas collected during each experiment was in good agreement with the volume of hydrogen assumed to be generated from the chemical reaction of lithium with the solvents.

scholarly journals Molecular Association of Tetramethylurea and Chlorobenzene Molecules in Microwave Frequency Range

2010 ◽  
Vol 65 (10) ◽  
pp. 854-858
Author(s):  
Vimal Sharma ◽  
Nagesh Thakur
Keyword(s):  
Relaxation Time ◽  
Dielectric Relaxation ◽  
Viscous Flow ◽  
Relaxation Process ◽  
Binary Mixtures ◽  
Variation Method ◽  
Dielectric Relaxation Time ◽  
Flow Process ◽  
Dielectric Relaxation Process ◽  
Energy Parameters

The dielectric constant ε´ and dielectric loss ε´´ of the binary mixtures of tetramethylurea (TMU) and chlorobenzene (CB) have been calculated at 9.883 GHz by using standard standing microwave techniques. Gopalakrishna’s single frequency concentration variation method has been used to calculate dipole moment μ and dielectric relaxation time τ for different mole fractions of TMU in the binary mixture at different temperatures of 25 °C, 30 °C, 35 °C, and 40 °C. The variation of dielectric relaxation time with the mole fraction of TMU in the whole concentration range of the binary mixtures was found to be non-monotonic. The solute-solute and solute-solvent type of molecular associations may be proposed based upon above observations. Using Eyring rate equations the energy parameters ΔH, ΔF, and ΔS for the dielectric relaxation process and the viscous flow process have been calculated at the given temperatures. It is found from the comparison of energy parameters that, just like the viscous flow process, the dielectric relaxation process can also be treated as a rate process.

Sign in / Sign up

Export Citation Format

Share Document