One of the major challenges in electrochemistry is to properly account for polarization of the electrical double layer that forms at an electrode-electrolyte interface, especially when interpreting the impedance spectra of biological molecules, electrolytes, or live cell suspensions. This double layer, which affects the measured impedance, is also known as the electrode polarization effect. Various methods of correcting for its effects on impedance data have been reported, including varying the spacing between electrodes, four-electrode techniques, and electrodeless methods. Here we discuss the use of a constant phase element in a recently proposed circuit model, which can be thought of as a measure of the fractal nature of the interface. We also report on the conductivity spectra of several saline solutions over the frequency range $1\mathrm{Hz}–1\mathrm{MHz}$, in which we observe Debye-like relaxation behavior that changes with ion concentration and type. Good agreement is obtained with an alternative model that treats the cations and anions as overdamped oscillators in harmonic restoring potentials. DOI: http://dx.doi.org/10.1103/PhysRevE.74.051505 © 2006 The American Physical Society

We have calculated the total critical current as a function of applied magnetic flux for a superconducting interferometer consisting of many Josephson junctions in parallel. An enhancement and narrowing of the periodic principal maxima in the critical current versus flux characteristic is predicted as the number of junctions in parallel increases, even when the effects of finite self- and mutual inductances and nonuniformity of the junction critical currents are included in the calculations. The possible application of the superconducting quantum interference grating, or SQUIG, for the detection of magnetic flux is discussed.

An adiabatic thermalization model is developed to describe a typical pulsed laser deposition (PLD) process. The interaction of atoms in the plume, ejected from the target, with those of the background gas (e.g., oxygen) is specifically considered. The model gives a physical definition of the “plume range,” which depends on the particular PLD system, and calculates the range values. One prediction is that when the target-to-substrate distance is optimized, the deposition rate exhibits an extremely weak dependence on pulse intensity and will always be about 1 Å per pulse.

Composite thick films of YBa₂Cu₃O_7−x and silver have been prepared on alumina substrates using a paint‐on method. It is found that thick films containing greater than about 10% silver by weight have greatly reduced normal resistivities for T>T_c (onset) and significantly enhanced T_c (R=0) as compared with undoped films processed under identical conditions. These results are interpreted in terms of enhanced grain growth and an improved coupling between grain boundaries because of proximity‐induced electron pairing in the silver regions.