Point Defects and Protonic Conduction in A3B'B”2O9 Compounds

1994 ◽  
Vol 369 ◽  
Author(s):  
Yang Du ◽  
A.S. Nowick
Keyword(s):  
Electrical Conductivity ◽  
Ir Spectra ◽  
Point Defects ◽  
Defect Structure ◽  
Complex Perovskite ◽  
Divalent Ions ◽  
Protonic Conduction ◽  
Protonic Conductors ◽  
Lower Activation ◽  
Perovskite Type

AbstractWe have investigated the defect structure and protonic transport properties of nonstoichiometric complex perovskite-type compounds of the type A3B'1+xNb2-xO9-δ. where A and B' are both divalent ions. Protons are incorporated by treatment in H2O vapor and their presence is manifested by the appearance of an OH band in the IR spectra, as well as by the large increase in electrical conductivity to produce excellent protonic conductors, with lower activation energies. A non-classical isotope effect, in which the Arrhenius plots for D+ and H+ cross over, can be explained by a modification of the classical ART hopping theory.

Electrical Conductivity of Proton Conductive Ceramics under Reactor Irradiation

2006 ◽  
Vol 45 ◽  
pp. 1974-1979 ◽  
Author(s):  
Tatsuo Shikama ◽  
Bun Tsuchiya ◽  
Shinji Nagata ◽  
Kentaro Toh
Keyword(s):  
Electrical Conductivity ◽  
Radiation Effects ◽  
Spectroscopic Techniques ◽  
Oxide Ceramics ◽  
Reactor Irradiation ◽  
Protonic Conduction ◽  
Conductive Ceramics ◽  
Electron Holes ◽  
Proton Migration ◽  
Perovskite Type

Electrical charges may be transported in ceramics by not only electrons but also by electron-holes, ions, and protons. Especially in nuclear fusion environments, electrical conductivity by proton migration (protonic conduction) will play an important role, as supply of hydrogen isotopes is sufficient and working temperature for ceramics will be in general high. In the present paper, radiation effects on the electrical conductivity of perovskite-type oxides will be reviewed, emphasizing radiation effects on transport behaviors of hydrogen and on reducing behaviors of oxide ceramics. Some perovskite-type oxides are known to have large protonic conductivity and an electrical charge state of some atomic elements composing them can be studied easily by spectroscopic techniques.

Role of point defects in the thermal decomposition of ammonium perchlorate

1968 ◽  
Vol 307 (1490) ◽  
pp. 303-315 ◽  
Keyword(s):  
Electrical Conductivity ◽  
Thermal Decomposition ◽  
Single Crystals ◽  
Ammonium Perchlorate ◽  
Point Defects ◽  
Defect Structure ◽  
Electrical Conductance ◽  
Charge Carriers ◽  
Point Defect Structure

The thermal decomposition of ammonium perchlorate has usually been described in terms of chemical reactions with the point defect structure of the solid ignored. Both the isothermal and adiabatic decompositions have been reinvestigated over the temperature range 200 to 450°C. There is a good correlation between the isothermal d. c. electrical conductance of single crystals, and of conductance as a function of temperature with the extent of decomposition, indicating that charge carriers play a significant role in the thermal decomposition. The study of the electrical conductivity as a function of temperature has resulted in the assignment of a probable defect structure to ammonium perchlorate: cationic Frenkel type below 250°C and Schottky disorder at higher temperatures. This suggests an explanation for the phenomenon of only 30% decomposition below 250°C and 100% above this temperature.

Defect structure and electrical conductivity of niobates with related perovskite-type structures

1984 ◽  
Vol 12 ◽  
pp. 113-118 ◽  
Author(s):  
J LECOMTE ◽  
J LOUP ◽  
G BOSSER ◽  
M HERVIEU ◽  
B RAVEAU
Keyword(s):  
Electrical Conductivity ◽  
Defect Structure ◽  
Perovskite Type

Hg1-xCdxTe: Defect Structure Overview

1990 ◽  
Vol 216 ◽  
Author(s):  
M.A. Berding ◽  
A. Sher ◽  
A.-B. Chen
Keyword(s):  
Point Defects ◽  
Defect Structure ◽  
Defect Formation ◽  
Activation Energies ◽  
Mass Action ◽  
Native Defect ◽  
Native Point Defects ◽  
Vacancy Migration ◽  
Formation Energies ◽  
Diffusion Activation

ABSTRACTNative point defects play an important role in HgCdTe. Here we discuss some of the relevant mass action equations, and use recently calculated defect formation energies to discuss relative defect concentrations. In agreement with experiment, the Hg vacancy is found to be the dominant native defect to accommodate excess tellurium. Preliminary estimates find the Hg antisite and the Hg interstitial to be of comparable densities. Our calculated defect formation energies are also consistent with measured diffusion activation energies, assuming the interstitial and vacancy migration energies are small.

ChemInform Abstract: IR Spectra and Electrical Conductivity of the Solid Solutions X MgO + (1-X) α-Nb2O5; 0.01 ≤ X ≤ 0.09.

ChemInform ◽  
2010 ◽  
Vol 23 (32) ◽  
pp. no-no
Author(s):  
Z. PARK ◽  
J. S. PARK ◽  
D. H. LEE ◽  
J. H. JUN ◽  
C. H. YO ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Ir Spectra ◽  
Solid Solutions

scholarly journals Silver vacancy concentration engineering leading to the ultralow lattice thermal conductivity and improved thermoelectric performance of Ag1-xInTe2

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Yaqiong Zhong ◽  
Yong Luo ◽  
Xie Li ◽  
Jiaolin Cui
Keyword(s):  
Crystal Structure ◽  
Thermal Conductivity ◽  
Electrical Conductivity ◽  
Point Defects ◽  
Lattice Thermal Conductivity ◽  
Vacancy Concentration ◽  
Antisite Defect ◽  
Thermoelectric Performance ◽  
Callaway Model

AbstractAgInTe2 compound has not received enough recognition in thermoelectrics, possibly due to the fact that the presence of Te vacancy (VTe) and antisite defect of In at Ag site (InAg) degrades its electrical conductivity. In this work, we prepared the Ag1-xInTe2 compounds with substoichiometric amounts of Ag and observed an ultralow lattice thermal conductivity (κL = 0.1 Wm−1K−1) for the sample at x = 0.15 and 814 K. This leads to more than 2-fold enhancement in the ZT value (ZT = 0.62) compared to the pristine AgInTe2. In addition, we have traced the origin of the untralow κL using the Callaway model. The results attained in this work suggest that the engineering of the silver vacancy (VAg) concentration is still an effective way to manipulate the thermoelectric performance of AgInTe2, realized by the increased point defects and modified crystal structure distortion as the VAg concentration increases.

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