Regensburg 2016 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
TT: Fachverband Tiefe Temperaturen
TT 19: Superconductivity: Poster Session
TT 19.6: Poster
Montag, 7. März 2016, 15:00–18:00, Poster D
Measuring the microwave response of superconducting Nb:STO and Ti at mK temperatures using superconducting resonators — •Markus Thiemann1, Manfred Beutel1, Martin Dressel1, Evangelos Fillis-Tsirakis2, Hans Boschker2, Jochen Mannhart2, and Marc Scheffler1 — 11. Physikalisches Institut, Universität Stuttgart — 2Max Planck Institute for Solid State Research, Stuttgart
Niobium doped SrTiO3 is a superconductor, with the lowest charge carrier density among all superconductors. It shows a dome in the transition temperature as a function of doping concentration with a maximum Tc≈ 0.3 K . The superconducting dome may originate from the different bands being occupied depending on the doping level. The low energy scales of the system, as indicated by the low Tc are within the GHz-regime. Therefore microwave measurements are a powerful technique to reveal the electronic properties of these superconductors.
We preformed microwave measurements on Nb:STO of different doping levels in a dilution refrigerator, using superconducting stripline resonators. Measurements were done in a temperature and frequency range from 40-400mK and 1-20GHz, covering the normal and superconducting states. For comparison we also measured the temperature dependence of the surface impedance of superconducting titanium (Tc≈ 0.5 K), which can be well described by the Mattis-Bardeen equations with a ratio 2Δ/kBTc=3.56. Therefore titanium is an ideal reference sample representing a conventional BCS-superconductor.