14 December 1992 Far-infrared and mid-infrared absorption in (Bi,Pb)-sr-(Ca,Y)-Cu-O
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Proceedings Volume 1929, 17th International Conference on Infrared and Millimeter Waves; 19290A (1992) https://doi.org/10.1117/12.2298127
Event: 17th International Conference on Infrared and Millimeter Waves, 1992, Pasadena, CA, United States
Abstract
The normal state electronic properties of High-Tc superconductors (HTCS) are not yet fully understood. In particular, the origin of a mid-infrared absorption band which has been observed in all of HTCS, and whose intensity and peak frequency do not depend on temperature, is still unexplained. In this work, we have measured at different temperatures, from 50 to 22000 cm-1, the reflectivity of films and single crystals belonging to the Bi-Sr-Ca-Cu-O family, looking for possible connections between the MIR band parameters and the superconducting properties of Bi-Sr-Ca-Cu-O. Thin films of the pure material, belonging to phases "0" (Tc=10 K), "1" (Tc=80 K) and "2" (Tc=95 K) have been measured. In addition, highly oriented films of phase 1 with Bi partially replaced by Pb, have been prepared and tested. In this way, a sequence of reflectivities curves corresponding to Tc's varying between 10 and 95 K, has been obtained. Finally, an insulating single crystal; where Ca has been fully replaced by Y, has been grown and studied in the infrared. It shows a broad charge-transfer band centered at 12000 cm-1, as observed in most HTCS parent compounds, and a sequence of phonons in the far-infrared which are quite similar to those observed in Nd-substituted Bi-Sr-Ca-Cu-O. [1]
© (1992) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
P. Calvani, P. Calvani, } "Far-infrared and mid-infrared absorption in (Bi,Pb)-sr-(Ca,Y)-Cu-O", Proc. SPIE 1929, 17th International Conference on Infrared and Millimeter Waves, 19290A (14 December 1992); doi: 10.1117/12.2298127; https://doi.org/10.1117/12.2298127
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