engleski

High-Temperature Superconducting Oxides: Their Thermal Treatment, Structural, Spectroscopic and Transport Properties

Three groups of high-temperature superconducting oxides: La_(2-x)Sr_xCuO_4, YBa_2Cu_3O_(7-delta) and Bi-Ca-Sr-Cu-O were prepared and their properties investigated. Solid state reaction of the starting components or coprecipitation methods were used in the preparation of superconducting samples. Thermal treatment of the components on the thermobalance gave insight into kinetic of alkaline-earth carbonates decomposition and the amount of oxygen present in the superconducting species. A method for the continuous control of the thermal reaction of the starting components is developed as well as the testing of high-quality superconducting samples. Two series of Bi-Ca-Sr-Cu-O systems were prepared, both with and without doping. The first one usually displays two Tc transitions, at 85 K and 110 K, while the second one, for suitable lead content and thermal treatment, as single high-Tc phase of 110 K was stabilized.

high-temperature superconductors; mixed-metal oxides; preparation; structural properties; transport properties

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