Markus Thiemann

Superconducting Pb stripline resonators in parallel magnetic field and their application for microwave spectroscopy

Planar superconducting microwave resonators are key elements in a variety of technical applications and also act as sensitive probes for microwave spectroscopy of various materials of interest. Here superconducting Pb is a suitable material as a basis for microwave stripline resonators. To utilize Pb stripline resonators in a variable magnetic field (e.g. in ESR), the electrodynamics of such resonators in finite magnetic field has to be well understood. Therefore we performed microwave transmission measurements on superconducting Pb stripline resonators in a variable, parallel magnetic field. We determined surface resistance, penetration depth as well as real and imaginary parts, \sigma

Niobium stripline resonators for microwave studies on superconductors

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Microwave study of superconducting Sn films above and below percolation

and \sigma

Superconducting coplanar microwave resonators with operating frequencies up to 50 GHz

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Broadband Corbino spectroscopy and stripline resonators to study the microwave properties of superconductors

, of the complex conductivity of superconducting Pb as a function of magnetic field. Here we find features reminiscent of those in temperature-dependent measurements, such as a maximum in \sigma

On-Chip ESR Measurements of DPPH at mK Temperatures☆

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One Kelvin means 21 GHz: Probing superconductors with low-frequency optics

(coherence peak). At magnetic fields above the critical field of this type-I superconductor we still find low-loss microwave response, which we assign to remaining superconductivity in the form of filaments within the Pb. Hysteresis effects are found in the quality factor of resonances once the swept magnetic field has exceeded the critical magnetic field. This is due to normal conducting areas that are pinned and can therefore persist in the superconducting phase. Besides zero-field-cooling we show an alternative way to eliminate these even at T<T

Single-Gap Superconductivity and Dome of Superfluid Density in Nb-Doped SrTiO3

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Complete electrodynamics of a BCS superconductor with μeV energy scales: Microwave spectroscopy on titanium at mK temperatures

. Based on our microwave data, we determine the critical magnetic field and the critical temperature of Pb in a temperature range between 1.6K and 6.5K and magnetic fields up to 140mT, showing good agreement with BCS predictions. We study a Sn sample in a Pb resonator to demonstrate the applicability of superconducting Pb stripline resonators in the experimental study of other (super-)conducting materials in a variable magnetic field.

Superconducting stripline resonators at frequencies up to 50 GHz for microwave spectroscopy applications

Microwave spectroscopy is a powerful experimental tool to reveal information on the intrinsic properties of superconductors. Superconducting stripline resonators, where the material under study constitutes one of the ground planes, offer a high sensitivity to investigate superconducting bulk samples. In order to improve this measurement technique, we have studied stripline resonators made of niobium, and we compare the results to lead stripline resonators. With this technique we are able to determine the temperature dependence of the complex conductivity of niobium and the energy gap