Oxygen permittivity

Here, v is the concentration of conductivity electrons in volume of the crystal, which equals to concentration of completely ionizing donor centers in Sn02 lattice and s is the Sn02 dielectric permittivity [93]. The height Fs is proportional to eN2 [97], where Ns is the concentration of adsorbed oxygen ions. The value... 

Typical concentrations of dopants (0.05-5 at.%) must result in the formation of dipolar pairs between an appreciable fraction of the dopant ions and the vacancies, e.g. 2La A-VA or 2Fel i+ -V( ). Donor-cation vacancy combinations can be assumed to have a stable orientation so that their initially random state is unaffected by spontaneous polarization or applied fields. Acceptor-oxygen vacancy combinations are likely to be less stable and thermally activated reorientation may take place in the presence of local or applied fields. The dipoles, once oriented in a common direction, will provide a field stabilizing the domain structure. A reduction in permittivity, dielectric and mechanical loss and an increase in the coercive field will result from the inhibition of wall movement. Since the compliance is affected by the elastic movement of 90° walls under stress, it will also be reduced by domain stabilization. 

Donor doping in PZT would be expected to reduce the concentration of oxygen vacancies, leading to a reduction in the concentration of domain-stabilizing defect pairs and so to lower ageing rates. The resulting increase in wall mobility causes the observed increases in permittivity, dielectric losses, elastic compliance and coupling coefficients, and reductions in mechanical Q and coercivity. 

By the time the third member of the series, poly(trimethylene oxide), is reached, dipole-dipole interaction along the chain is very weak indeed, and the trans-conformation is slightly more favoured energetically (by about 4 kJ mol-1). Since the trans-conformation involves parallel alignment of the oxygen dipoles, the observed decrease of relative permittivity with temperature is expected. 

Finally, in poly(tetramethylene oxide), the trans-conformation is again the most favoured, but here the trans-conformation incurs anti-parallel alignment of the oxygen dipoles. The relative permittivity therefore increases with temperature. 

The overall conclusion that, with respect to all water-shunning or hydro-phobic phases studied so far, water turns its oxygen away from the water phase must mean that this is mainly a property of the water and not of water-adjacent phase interaction. For hydrophilic surfaces, containing donors actively promoting the formation of hydrogen bridges, this may be different. Information from inner layer capacitances, suggesting that the relative dielectric permittivity of water adjacent to silver iodide and mercury is much lower than It is for oxides, may be in line with this. 

One of the first attempts at modeling SOFCs with KMC simulations was reported by Modak and Lusk [32]. In their study, their model was restricted to capture the behavior of the electrolyte, YSZ, as a function of the open-circuit voltage, and comparisons were made with analytical predictions (Guoy-Chapman model). The paper focused on the oxygen concentration distribution within the electrolyte at the TPB, the voltage profile across the electrolyte, and the electric field within the electrolyte. Furthermore, the influences of the temperature and relative permittivity of the electrolyte on these features were captured. In order to accelerate the convergence of the simulations and to facilitate comparison with analytic models, a one-dimensional (1-D) model was implemented, and the cathode and anode structures and reactions were completely neglected. 

It is clear that the physical properties of water are very much influenced by the important role played by hydrogen bonding in determining its structure. These properties include the high dielectric permittivity, which cannot be explained on the basis of dipole-dipole interactions alone. It is also clear that electrolytes have a very disruptive effect on water structure. Cations are solvated by the lone electron pairs on the oxygen atom of the water molecule and thus cause considerable disruption in the local water structure. This leads to changes in the bulk physical properties of water, such as its permittivity. 

Polar solvents are those liquids whose relative permittivity is sufficiently high that electrolytes can be dissolved in them. The best-known example of such a liquid is water. The oxygen end of this simple molecule is electron-rich and can stabilize cations. The hydrogen atoms are electron-poor and thus are involved in the solvation of anions. The structure of pure water is very much influenced by the... 

Additionally, low-temperature oxides (LTO) were examined. The deposition process uses triethylsilane and oxygen at 550 °C. Table 18.1 gives an overview of the different inorganic gate dielectrics, their deposition temperatures, the deposited layer thicknesses and their permittivities. 

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