High-temperature superconductors for microwave devices.
The modern application of superconductors, such as microwave devices, demand working temperatures higher than the ones for classic superconductors. Problems arise when, at high temperatures, superconductors lose their “superconductivity”, attained only at low temperatures. Therefore, in cases where high working temperatures are required, scientists propose the use of high temperature superconductors. Increasing the purity and definition of the particle size of high temperature superconductors consequently provides materials with high transport current densities. The chemical manufacture of high temperature superconductor devices determines to a large extent their performance. Scientists have studied the relation between the chemistry and the microstructure of such superconductors. Thin films were obtained on coherent substrates and their structure was studied using high resolution electron microscopy and electron diffraction. Scientists observed that a number of oxide systems, unstable in bulk, were stabilized in thin film state. A special technique was developed for depositing superconducting oxide films, simultaneously, at both sides of the substrate. The electrical properties of the thin film materials were found to be correlating with the observed peculiarities of microstructure. The results of this research contribute to the development of new and alternative chemical manufacturing techniques to enhance transport current densities of high temperature superconductors used as materials for high current and microwave applications.