Search

Electric forming and telegraph noise in tunnel junctions were investigated. The results showed that normal state resistance can be altered by applying enough high voltage across the oxide barrier. The low-frequency noise spectrum underwent a significant change before and after electrical forming. Two-level signals could be created and destroyed through the application of a 2.5x10(super 8) V/m electric field.

Focuses on a study which fabricated a double-barrier niobium tunnel junctions for quasiparticle mixers. Description of the fabrication process; Analysis of current-voltage curves; Discussion on the mixer experiments.

Investigates resonance steps in the current-voltage (I/V) characteristics of single junctions and arrays of two superconductor-insulator-superconductor junctions. Description of the inductive tuning structures; Resonance steps in the I/V characteristics; Resonance effects in series arrays.

Presents a study which reported the increase of the normal-state resistance of niobium (Nb)-aluminum/AlO[subx]-Nb tunnel junctions by annealing at elevated temperatures. Method used in fabricating the junctions; Details on annealing in air and nitrogen; Nitridation of Nb microstrips.

Describes the properties of superconductor-insulator-normal (SIN) conductor junctions made from niobium-aluminum (Al)/Al-oxide-Al trilayers. Lowest double sideband receiver noise temperature; Incidence of energy gap in the Al counter electrode; Fabrication of SIN junctions.

A correction to the article "Electric forming and telegraph noise in tunnel junctions" that was published in a previous issue is presented.

We report on the change of normal resistance in tunnel junctions brought about by the application of a sufficiently large voltage at temperatures of 4.2 K and lower. This effect can be of use in various branches of electron and Cooper-pair tunneling, including the optimization of quasiparticle mixers. The voltage-induced change of the normal resistance can be reversed by warming up the sample to room temperature. [ABSTRACT FROM AUTHOR]

This letter reports a low noise submillimeter-wave mixer using NbN tunnel junctions integrated in Nb matching circuits. The double side band receiver noise temperature was 245 K at 345 GHz. Plasma conditions for NbN film deposition on quartz substrates at room temperature are created by using a second Nb target as a selective nitrogen pump. Electrodes for tunnel junctions with critical temperatures above 15 K and normal state resistivities in the range from 130 to 160 μΩ cm were obtained. This permits integrating NbN junctions into normal metal or non-NbN superconducting matching circuits, which is of great interest for THz mixers. © 1996 American Institute of Physics. [ABSTRACT FROM AUTHOR]

The serum concentration of squamous-cell-carcinoma antigen (SCC) and carcinoembryonic antigen (CEA) in 51 patients with squamous cell carcinoma of the oral cavity were compared to those of 53 patients with non-malignant disorders of the head and neck. The sensitivity found for SCC was only 24%, but was much higher than for CEA. SCC could be a valuable tool in follow-up monitoring of patients treated for squamous cell carcinomas of the oral cavity.