1 October 1991 High Tc superconductors
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Proceedings Volume 1576, 16th International Conference on Infrared and Millimeter Waves; 157616 (1991) https://doi.org/10.1117/12.2297755
Event: 16th International Conference on Infrared and Millimeter Waves, 1991, Lausanne, Switzerland
Abstract
After four years of world wide research on high Tc, superconductors of the cuprate type a variety of different material families is known, with Tc values up to 125 K. Progress in material preparation and in the development of experimental and theoretical methods has lead to a basic understanding of various material properties, however, the nature of the pairing mechanism is yet unknown. In this paper some basic properties will be discussed. A second point will be concentrated on important optical properties from microwave to u.v. frequencies. Condensation of charge carriers can be accompanied with anomalous phonon behavior; at Tc anomalous changes of oscillator strengths of infrared active phonons and anomalous shifts of resonance frequencies of some phonons are observed. Condensation of charge carriers leads, furthermore, to a behavior of the (anisotropic) optical properties that may be described by superconducting energy gaps. For excitations along the copper oxide planes the optical properties can be described as arising from a superconducting energy gap 2∆(0)/kTc≈7 . However, there remains at low temperatures intra-gap absorption that extends from microwave to far-infrared frequencies. In a third part of the paper, microwave and far-infrared applications of high Tc superconductors will be discussed, namely microwave antennas, Fabry-Perot filters and
© (1991) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Karl F. Renk, "High Tc superconductors", Proc. SPIE 1576, 16th International Conference on Infrared and Millimeter Waves, 157616 (1 October 1991); doi: 10.1117/12.2297755; https://doi.org/10.1117/12.2297755
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