Regensburg 2013 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 58: Poster Session Transport & Matter at Low Temperature

TT 58.29: Poster

Thursday, March 14, 2013, 15:00–19:00, Poster D

Hysteresis effects in superconducting resonators — •Philipp Mayer¹, Fengbin Song¹, Martin Weides¹, Hannes Rotzinger¹, Michael Stüber², Harald Leiste², and Alexey V. Ustinov¹ — ¹Physikalisches Institut, Karlsruher Institut für Technologie, Center for Functional Nanostructures — ²Angewandte Werkstoffphysik, Karlsruher Institut für Technologie

Superconducting microwave resonators are of considerable interest for quantum circuits. They can be used for many applications in circuit quantum electrodynamics, for example as a readout tool for qubits, a quantum bus or a coupling to spins in crystals. For these purposes, it is important to understand the behavior of superconducting resonators in magnetic fields. Previous studies on resonators made of Nb have shown a hysteretic dependence of quality factor and resonance frequency on applied magnetic field. High quality microwave resonators are made of TiN and can have high internal quality factors in the order of 10⁷ at high and 10⁶ at low photon numbers. Furthermore they were shown to have a large kinetic inductance. In this work, 40 nm thin films of TiN were sputtered on intrinsic Si wafers. The films were patterned by reactive ion etching into resonators of λ/2, λ/4 and lumped LC geometry. We investigated their hysteretic behavior in out-of-plane magnetic fields at temperatures ranging from 275 mK up to 1K in both the many photon and single photon limit. We will present and discuss results of our on-going experiments.