The mid-infrared dielectric function of NBCO in the a-b plane from 85 K to 300 K

• Published in: Superconductor science & technology 2001-03, Vol.14 (3), p.130-138
• Main Authors: Cairns, G F, Dawson, P, O'Prey, S M, Romans, E J
• Format: Article
• Language: English
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Electronic structure; Exact sciences and technology; High-tc films; Physics; Properties of type I and type II superconductors; Superconducting films and low-dimensional structures; Superconductivity
• ISSN: 0953-2048; 1361-6668
• DOI: 10.1088/0953-2048/14/3/303

Results are reported on the a-b plane dielectric function (epsilon) of thin-film c-axis NdBa2Cu3O7-d with close to optimal O doping (Tc approx equals 90 K) in the mid-ir (wavelength 3.392 mu m) at 85-300 K. An attenuated total reflectance technique based on the excitation of surface plasmon polaritons is used. Results show that epsilonr decreases quasi-linearly with increasing temperature, while epsiloni is invariant with temperature to within experimental uncertainties. Representative values are epsilon = [epsilonr + iepsiloni] = (-12.9plus/minus 0.6) + i(23.0plus/minus 1.5) at T approx equals 295 K and epsilon = (-15.7plus/minus 0.7) + i(23.5plus/minus 1.1) at T approx equals 90 K. The raw data are interpreted in terms of the generalized Drude model which gives effective scattering rates (1/t*) that increase with temperature from about 3800 cm-1 at 90 K to about 4300 cm-1 at 295 K. 44 refs.