Magnetic field robust high quality factor NbTiN superconducting microwave resonators
Manuel Müller, Thomas Luschmann, A Faltermeier, Stefan Weichselbaumer, Linda Koch, Gerhard B. P. Huber, H. W. Schumacher, Niels Ubbelohde, David Reifert, Thomas Scheller, Frank Deppe, Achim Marx, Stefan Filipp, Matthias Althammer, R Gross, Hans Huebl
Abstract
Abstract We systematically study the performance of compact lumped element planar microwave Nb 70 Ti 30 N (NbTiN) resonators operating at 5 GHz in external in-plane magnetic fields up to 440 mT, a broad temperature regime from 2.2 K up to 13 K, as well as mK temperatures. For comparison, the resonators have been fabricated on thermally oxidized and pristine, (001) oriented silicon substrates. When operating the resonators in the multi-photon regime at T = 2.2 K, we find internal quality factors Q int ≃ 2 × 10 5 for NbTiN resonators grown on pristine Si substrates. In addition, we investigate the Q -factors of the resonators on pristine Si substrates at millikelvin temperatures to assess their applicability for quantum applications. We find Q int ≃ 2 × 10 5 in the single photon regime and Q int ≃ 5 × 10 5 in the high power regime at T = 7 mK. From the excellent performance of our resonators over a broad temperature and magnetic field range, we conclude that NbTiN deposited on Si (100) substrates, where the surface oxide has been removed, constitutes a promising material platform for electron spin resonance and ferromagnetic resonance experiments using superconducting planar microwave resonators.