Electrical Conductivity and Thermogravimetric Studies of the High-7c Superconductor YBa2Cu3Ox

1987 ◽  
Vol 99 ◽  
Author(s):  
Y. H. Han ◽  
D. W. Monroe

ABSTRACTNonstoichiometry in YBa2Cu3Ox has been studied by means of equilibrium electrical conductivity and thermogravimetric method. We have observed a strong correlation between electrical resistivity and oxygen stoichiometry (x) at high temperature. Electrical resistivities increase linearly from the superconducting onset tcmperature(100 K) to 450 C where oxygen starts to evolve from this material, and then begin to deviate from linear temperature dependence. The experimental results indicate that electrical resistivity in this material is associated with the defect species (charge carrier) population due to oxygen stoichiometry. Electrical conductivities were also measured as a function of oxygen partial pressure (1 to 10−4 atm) at various temperatures. At P(OI) > 101 atm the conductivity shows a l/4th slope dependence on oxygen partial pressure while at P(0;) < 10 f atm the conductivity is proportional to P(O2)1/2- The conductivity behavior with oxygen stoichiometry suggests that the electron holes associated with Cu+ play an important role as charge carriers in this material, and even at x < 6.5 p-typc conduction is predominant.

1957 ◽  
Vol 35 (3) ◽  
pp. 248-257 ◽  
Author(s):  
G. K. White ◽  
S. B. Woods

Measurements are reported of the thermal and electrical conductivities of the transition elements Rh, Ir, Pt in a state of high purity; the rapid rate of decrease of the "ideal" thermal and electrical resistivities with temperature, particularly in Rh and Ir, suggests that s–d transitions are not a dominant resistive mechanism at low temperatures in these metals, in contrast to palladium, iron, and nickel, which were studied previously. The electrical resistivity of platinum is in general agreement with the earlier results of de Haas and de Boer (1934); the quadratic dependence on temperature observed below about 10° K. suggests that electron–electron collisions may well be an important factor in this metal.


1994 ◽  
Vol 369 ◽  
Author(s):  
Igor Kosacki ◽  
Harry L. Tuller

The results of electrical conductivity measurements on Nb, W, and Mn-doped Gd2Ti2O7 are presented. A correlation between electrical conductivity, the oxygen partial pressure and type of dopants has been obtained. The source of the different PO2 dependence for Mn-doped material is discussed.


2020 ◽  
Vol 22 (15) ◽  
pp. 8219-8232
Author(s):  
Christian Pithan ◽  
Hayato Katsu ◽  
Rainer Waser

The electrical conductivity of donor-doped BaTiO3 thermistor ceramics with excessive BaO revealing a reduction-persistent PTCR effect has been carefully examined depending on materials’ composition and oxygen partial pressure at moderate temperatures between 973 and 1273 K.


1989 ◽  
Vol 44 (1) ◽  
pp. 26-28 ◽  
Author(s):  
G. Chiodelli ◽  
G. Campari-Viganò ◽  
V. Massarotti ◽  
G. Flor

Abstract The electrical behaviour of La2-xSrxCuO4-y solid solutions (with x = 0, x = 0.025, x = 0.05, and x = 0.15) at temperatures between 10 and 900 K and under different oxygen partial pressure pO2 = 1 ÷ 10-6 atm) has been investigated. The samples prepared and measured under an O2 flux (i.e., with y = 0) show a superconducting transition with Tc = 46, 29. 37 K for x = 0. 0.05 and 0.15, respectively. The samples with x = 0.025, y = 0, and x = 0, y ≠ 0 exhibit no sign of superconductivity. In the temperature range 100-900 K. La2CuO4 is semiconducting, whereas the electrical resistivity is independent of temperature for the x =0.025 sample, and the x = 0.05 and x = 0.15 are metallic.


1966 ◽  
Vol 44 (8) ◽  
pp. 1685-1698 ◽  
Author(s):  
T. Matsumura

The ionic transport number and the d-c. electrical conductivity of single-crystal and polycrystalline alumina have been studied between 1 000 °K and 1 750 °K at an oxygen partial pressure of 0.2 atm. The ionic transport number was determined by the galvanic-cell e.m.f. measurements; the electrical conductivity was measured by the three-terminal method.It was found that alumina is a mixed conductor, being predominantly an ionic conductor at temperatures below 1 100 °K and predominantly electronic at temperatures higher than 1 600 °K. The activation energies found for the electrical conductivity of the single-crystal and polycrystalline specimens are 0.8 eV and 2.4 eV respectively in the ionic range and 3.0 eV and 3.7 eV in the electronic range.


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