Temperature dependence of the millimeterwave conductivity of YBa2Cu3O7 and Bi2Sr2Ca1Cu2O8 Thin films at 300 GHZ

✍ Scribed by U. Dähne; T. Amrein; Y. Goncharov; N. Klein; G. Kozlov; L. Schultz; N. Tellmann; K. Urban

• Publisher: Elsevier Science
• Year: 1994
• Tongue: English
• Weight: 170 KB
• Volume: 235-240
• Category: Article
• ISSN: 0921-4534
• DOI: 10.1016/0921-4534(94)92254-3

✦ Synopsis

A millimeterwave spectrometer using continuously tunable backward wave oscillators as sources and a quasioptical interferometer in the Mach-Zehnder configuration was used to measure the transmittivity in amplitude and phase of 60nm thin YBa2Cu307 and 250nm thin Bi2Sr2CalCU208 films on NdGaO 3 substrates at 300GHz for temperatures between 4K and 300K. From the spectra we derived the real and imaginary part of the dynamic conductwity o=at+io 2 in the normal and superconducting state. From o 2 we got absolute values for the London penetration depth X. Beside the lower at(T) values for the BSCCO films over the entire temperature range a clear maximum in at(T) was measured at 60K for both compounds. The ~,(T) values of the BSCCO tdms are more than a factor of two higher in comparision to YBCO. Using a Drude-model for the normal mid superconducting state a strong temperature decrease of the quasiparticle scattering rate zt(T) below T c was observed for both compounds, whexeas the absolute rI(T) values are smaller for the BSCCO-films.