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 ◽  
...  
1996 ◽  
Vol 453 ◽  
Author(s):  
A. R. Guo ◽  
Z. -Y. Cheng ◽  
R. S. Katiyar ◽  
Ruyan Guo ◽  
A. S. Bhalla

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.


2021 ◽  
Vol 96 ◽  
pp. 107093
Author(s):  
Vera P. Pavlović ◽  
Dragana Tošić ◽  
Radovan Dojčilović ◽  
Duško Dudić ◽  
Miroslav D. Dramićanin ◽  
...  

2010 ◽  
Vol 65 (10) ◽  
pp. 854-858
Author(s):  
Vimal Sharma ◽  
Nagesh Thakur

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.


2013 ◽  
Vol 103 (11) ◽  
pp. 112908
Author(s):  
Shiguang Yan ◽  
Chaoliang Mao ◽  
Genshui Wang ◽  
Chunhua Yao ◽  
Fei Cao ◽  
...  

2016 ◽  
Vol 846 ◽  
pp. 311-317
Author(s):  
Mohd Noor Mat ◽  
M.K. Halimah ◽  
Wan Mohd Daud Wan Yusoff ◽  
H. Mansor ◽  
H. Nizam ◽  
...  

Dielectric relaxation and conductivity of Ni0.3Zn0.7Fe2O4 (NZF) were studied in the frequency range between 0.01 Hz to 3 MHz and temperature range within 313 K to 473 K. The sample was prepared by mixing Zinc Oxide, Nickel Oxide and Iron Oxide and sintered at 1573 K for 10 hours long. Dielectric properties were studied using Novo Control Dielectric Spectrometer. Dielectric relaxation and conductivity phenomena were discussed using an empirical model to key out the dielectric relaxation process. Analyze peak frequency relaxation process consist of four slopes to explain the dielectric relaxation process. The conductivity of the sample indicates an activated process and activation energy of dc conductivity is 0.44 ± 0.01 eV.


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