Features of nanocontact formed using point electrical breakdown of a niobium oxide nanolayer

The electrical characteristics of a point section of niobium oxide between a massive cathode made of a superconducting indium-tin alloy and a niobium film before the oxide breakdown and the nanocontact that appears after the breakdown of the oxide at room temperature have been studied. The dependences of the point breakdown voltage of the oxide and the resistance of nanocontacts on the method of breakdown and the thickness of the oxide in the range of 15-60 nm have been established. In particular, a minimum value of the breakdown current has been established (about 1 {\mu}A), below which breakdown does not occur. The voltage-current characteristic (VCC) of the oxide has a semiconductor character and indicates the dependence of the breakdown voltage of the oxide on its polarity. The VCC of the nanocontact is nonlinear, which is associated with phase transitions in the nanocontact material caused by its heating by the transport current.Comment: 19 pages, 10 figure

Combined breakdown of a dielectric nanolayer to form a Josephson bridge

Electrical breakdown of a dielectric nanolayer between film electrodes under the combined action of direct current and capacitor discharge current makes it possible to form Josephson bridges with a reproducible resistance exceeding 1 {\Omega}. A new feature of the formation of a bridge during electrical breakdown, which is preceded by a series of preliminary breakdowns (auto breakdowns) of a dielectric nanolayer, has been discovered. The mechanism of the process and the role of the thickness of the cathode film in the formation of the bridge are discussed.Comment: 10 pages, 4 figure