High Tc Oxide Solid State Reaction Kinetics Via Complex Impedance Spectroscopy

1989 ◽  
Vol 169 ◽  
Author(s):  
E. A. Cooper ◽  
T. O. Mason ◽  
U. Balachandran ◽  
M. L. Kullberg

AbstractImpedance spectra (5Hz ‐ 13MHz) were collected during the solid state reaction of Yba2Cu2O6+y from large monosized CuO particles imbedded in a finely divided Y2 O3 /BaCO3 matrix. No particle size effect was observed, but a large temperature effect was observed corresponding to an activation energy of approximately 1.8eV (175kJ/mol) over the range 700‐900°C.

1984 ◽  
Vol 62 (6) ◽  
pp. 1227-1228
Author(s):  
M. Sunitha Kumari ◽  
Etalo A. Secco. I

not available


2014 ◽  
Vol 2014 ◽  
pp. 1-8
Author(s):  
Jan Večeřa ◽  
Iveta Šedová ◽  
Petr Mikulášek ◽  
Petra Šulcová

Rutile pigments Ti1-3xCrxNb2xO2±δ (where x=0, 0.05, 0.10, 0.20, 0.30 and 0.50) prepared by solid-state reaction are investigated. Chromium is chromophore (coloring ion) and niobium is counterion (charge-compensating element for electroneutrality). The effect of composition (x), calcination temperature (850, 900, 950, 1000, 1050, 1100 and 1150°C), and starting titanium compounds (anatase TiO2, hydrated anatase paste, TiOSO4·2H2O, and hydrated Na2Ti4O9 paste) on their color properties into organic matrix and particle size distribution was observed. According to the highest chroma C and visual color evaluation, yellow and orange pigments were selected as in color the most interesting. They have concentration x=0.05 or 0.10 and are prepared from anatase TiO2 and TiOSO4·2H2O at temperature ≥1050°C.


2009 ◽  
Vol 23 (26) ◽  
pp. 5179-5189
Author(s):  
K. JAWAHAR ◽  
BANARJI BEHERA ◽  
R. N. P. CHOUDHARY

Polycrystalline La 3/2 Bi 3/2 Fe 5 O 12 (LBIO) compound was prepared by a high-temperature solid-state reaction technique. The complex impedance of LBIO was measured over a wide temperature (i.e., room temperature to 500°C) and frequencies (i.e., 102–106 Hz) ranges. This study takes advantage of plotting ac data simultaneously in the form of impedance and modulus spectroscopic plots and obey non-Debye type of relaxation process. The Nyquist's plot showed the presence of grain effects in the material at high temperature. The ac conductivity spectrum was found to obey Jonscher's universal power law. The dc conductivity was found to increase with rise in temperature. The activation energy of the compound was found to be 0.24 and 0.51 eV in the low and high-temperature region, respectively, for conduction process.


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