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The study provides a better understanding of all the nonlinearities arising in the microwave response of the superconductors by the process of intermodulation (IMD) distortion. The analysis reveals that the use of a dopant can highly improve the power handling capacity of the system.

YBa2Cu3O7-delta grain boundary Josephson junctions are grown on SrTiO3 and MgO bicrystal substrates by the buffer layer introduction technique and subsequently examined for their superconducting transport properties. Current-voltage measurements are performed to evaluate the effect of the layer structures on the junctions' superconductive behavior. Results show that the presence of the buffer layers improves the superconducting transport properties of the Josephson junctions on both types of substrates.

The electric field effect of a multilayer structure exhibiting the same characteristics as that of metal-oxide semiconductors (MOS) was studied. The thin epitaxial c-axis films that compose the MOS-like structure were made using the inverted cylindrical magnetron sputtering process. Experimental measurements on the resistance and gate current at three different gate voltages of the MOS-like structure were conducted at various stabilized temperatures. Results indicate that a slow charge transfer effect takes place at temperatures above 200K.

The ultrafast non bolometric-response of YBa2Cu3O7 epitaxial thin films under infrared light illumination was studied. A continuous bias current was made to flow through several thin film samples placed inside a gas-flow cryostat with optical windows and irradiated by an infrared light source. The resulting voltage was measured at the end of the coaxial lines. Results show that the thin films have very fast response to light pulses, making them highly suitable in photodetector applications.

High-resolution spectra from 20 to 200 cm to the -1 for temperatures from 10 to 300 K give interference fringes that cannot be fitted by previous analysis in terms of four Lorentz oscillators. Parameters in the theory are revised to give a better fit both to the far IR and to the reststrahlen spectra.

Measures the photoresponse of epitaxial yttrium barium[sub 2]copper[sub 3] oxygen[sub 7-x] thin film. Mechanism shaping the voltage curves during the first hundred picoseconds; Influence of operating condition on the photoresponse; Confirmation of published analysis on biexponential escape phenomena of deposited energy.

We present a fabrication method of superconducting quantum interference devices (SQUIDs) based on direct write lithography with an atomic force microscope (AFM). This technique involves maskless local anodization of Nb or NbN ultrathin films using the voltage biased tip of the AFM. The SQUIDs are of weak-link type, for which two geometries have been tested: Dayem and variable thickness nanobridges. The magnetic field dependence of the maximum supercurrent Ic(Φ) in resulting SQUIDs is thoroughly measured for different weak link geometries and for both tested materials. It is found that the modulation shape and depth of Ic(Φ) curves are greatly dependent on the weak link size. We analyze the results taking into account the kinetic inductance of nanobridges and using the Likharev–Yakobson model. Finally we show that the present resolution reached by this technique (20 nm) enables us to fabricate Nb weak-links which behavior approaches those of ideal Josephson junctions. [Copyright &y& Elsevier]