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TT: Fachverband Tiefe Temperaturen
TT 27: Superconductivity: Cuprate Superconductors
TT 27.2: Talk
Wednesday, March 28, 2012, 11:45–12:00, H 2053
Optical investigation of nominally undoped Pr2CuO4 films — •G. Chanda1, A. V. Pronin1, R. P. S. M. Lobo2, J. Wosnitza1, H. Yamamoto3, and M. Naito4 — 1Dresden High Magnetic Field Laboratory (HLD), Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany — 2LPEM, ESPCI-ParisTech, CNRS, UPMC, Paris, France — 3NTT Basic Research Laboratories, NTT Corporation, Kanagawa, Japan — 4Department of Applied Physics, Tokyo University of Agriculture and Technology, Tokyo, Japan
Superconducting Pr2CuO4 films with T′ structure and Tc beetween 25 and 27 K have been investigated by different optical methods in a wide frequency range (5 – 55000 cm−1) and for temperatures from 2 to 300 K. From the infrared reflectivity spectra, a superconducting gap of 2Δ0 = 17 meV = 7.4 kB Tc is estimated. Absolute values of the London penetration depth (λL) have been calculated from phase-sensitive teraherz measurements. The zero-temperature limit of λL is 1.6 µm. The overall temperature dependence of λL shows a behavior typical for the cuprates. However, a closer look on the penetration depth at low temperatures reveals a flattening of the temperature dependence. We find λL(T)∝ Tn with n = 2.8 ± 0.2.