Influence of High Oxygen Partial Pressure on the Positive Temperature Coefficient Resistivity of BaTiO3

1991 ◽  
Vol 251 ◽  
Author(s):  
Ben Huybrechts ◽  
K. Ishizaki ◽  
M. Takata
Keyword(s):  
Oxygen Partial Pressure ◽  
Partial Pressure ◽  
Grain Boundaries ◽  
Temperature Coefficient ◽  
Arrhenius Plot ◽  
Positive Temperature Coefficient ◽  
High Oxygen ◽  
Positive Temperature ◽  
High Oxygen Partial Pressure ◽  
Partial Pressures

ABSTRACTThe influence of high oxygen partial pressures on the PTC behavior of non acceptor doped BaTiO3 is studied by using oxygen-hot-isostatic-press (O2-HIP). Annealing in high oxygen partial pressures increased the maximum resistivity with a factor 3, also the minimum resistivity and the gradient in the Arrhenius plot, i.e. resistivity versus the reciprocal of the temperature, increased. The results are analyzed using the well accepted Heywang model. The changes after O2-HIPping can be explained with an increase in acceptor density at the grain boundaries.

Electrical Conduction Properties of Liquid Vanadates. I. Vanadium Pentoxide

1972 ◽  
Vol 50 (17) ◽  
pp. 2865-2870 ◽  
Author(s):  
R. C. Kerby ◽  
J. R. Wilson
Keyword(s):  
Oxygen Partial Pressure ◽  
Partial Pressure ◽  
Temperature Coefficient ◽  
Vanadium Pentoxide ◽  
Electrical Conduction ◽  
Pressure Coefficient ◽  
Positive Temperature ◽  
Temperature Range ◽  
Partial Pressures ◽  
Conduction Properties

The electrical conductivity of liquid vanadium pentoxide was measured as a function of temperature and oxygen partial pressure. A positive temperature coefficient and a negative oxygen partial pressure coefficient of conduction were found for the temperature range 670 to 1000 °C and oxygen partial pressures from 0.1 to 1.0 atm. The activation energy of conduction was 0.77 eV and the oxygen partial pressure coefficient was −0.16. At oxygen partial pressures less than 0.1 atm, for the same temperature range, a negative temperature coefficient and a negative oxygen partial pressure coefficient of conduction were found.An n-type semiconduction model was used to explain the electrical conduction properties of liquid vanadium pentoxide at oxygen partial pressures greater than 0.1 atm. At lower oxygen partial pressures, electrical conduction was considered to occur by collective-electron conduction in partially filled 3d bands, due to an overlapping of the diffuse valence and conduction bands. The overlapping could result from a decrease in the cation separation distance in the melt due to the removal of oxygen ions from the melt.

Accumulation of bialaphos intermediates under high oxygen partial pressure and their conversion to bialaphos

1991 ◽  
Vol 71 (6) ◽  
pp. 433-435 ◽  
Author(s):  
Hidehi Takebe ◽  
Osamu Hiruta ◽  
Mihoko Matsunaga ◽  
Atsuyuki Satoh ◽  
Hideo Tanaka
Keyword(s):  
Oxygen Partial Pressure ◽  
Partial Pressure ◽  
High Oxygen ◽  
High Oxygen Partial Pressure

Microstructures in (Y0.95Ca0.05)Ba2Cu4O8 prepared by low and high oxygen partial pressure techniques

1990 ◽  
Vol 169 (3-4) ◽  
pp. 289-293 ◽  
Author(s):  
Koji Yamaguchi ◽  
Takayuki Miyatake ◽  
Takahiro Wada ◽  
Nobuo Suzuki ◽  
Tsutomu Takata ◽  
...  
Keyword(s):  
Oxygen Partial Pressure ◽  
Partial Pressure ◽  
High Oxygen ◽  
High Oxygen Partial Pressure

AgO Doped YBa2Cu4O8 Superconductor Under High Oxygen Partial Pressure

1991 ◽  
Vol 251 ◽  
Author(s):  
Yuichi Sawai ◽  
K. Ishizaki ◽  
M. Takata ◽  
A. Kuzjukevics
Keyword(s):  
Critical Temperature ◽  
Critical Current Density ◽  
Oxygen Partial Pressure ◽  
Partial Pressure ◽  
Critical Current ◽  
Current Density ◽  
High Oxygen ◽  
Silver Doping ◽  
High Oxygen Partial Pressure ◽  
Pressing Method

ABSTRACTGeneraly silver doping into YBa2Cu3O7 superconductor improves the critical temperature and critical current density. In this work the silver peroxide was doped into YBa2Cu4O8 superconductor and sintered by the Oxygen Hot Isostatically Pressing method. The critical temperature of the 124 phase increased by silver peroxide doping.

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