Far-infrared magneto-optical measurements of superconducting NbN layer

0342575 - FZÚ 2012 RIV CZ eng C - Conference Paper (international conference)
Koláček, Jan - Skrbek, L. - Šindler, M. - Tesař, Roman
Far-infrared magneto-optical measurements of superconducting NbN layer.
WDS ’09 Proceedings of Contributed Papers. Part III. Praha: MATFYZPRESS, 2009 - (Šafránková, J.; Pavlů, J.), s. 124-129. ISBN 978-80-7378-103-3.
[Annual conference of doctoral students - WDS 2009 /18./. Prague (CZ), 02.06.2009-05.06.2009]
R&D Projects: GA ČR GA202/08/0326
Institutional research plan: CEZ:AV0Z10100521
Keywords : far-infrared transmission * NbN * superconducting film * magnetic vortices
Subject RIV: BM - Solid Matter Physics ; Magnetism

Temperature dependence of far-infrared transmission of thin layer NbN deposited on SiO2 substrate has been measured at frequencies 0.40, 0.65 and 2.52 THz. The zero magnetic field data are in agreement with previous measurements. Additionally, temperature dependent transmission at 0.40 THz for parallel and perpendicular magnetic field orientation with respect to NbN layer from 1 to 10 tesla is reported. In order to interpret our data, we have calculated the transmission of the NbN layer using equations for complex conductivity. For zero magnetic field, the experimental and computed data are in good agreement. With increasing field, however, the experimental data start to deviate from the model prediction that neglects effects due to quantized vortices penetrating the superconductor. When moving, they absorb energy and affect both reflection and transmission. Presently, no way of calculating the complex conductivity in the presence of quantized vortices from the BCS theory is known.
Permanent Link: http://hdl.handle.net/11104/0185276