We have optimized the growth of superconducting TaN thin films on \ch{SiO2} substrates via dc magnetron sputtering and extract a maximum superconducting transition temperature of Tc=5 K as well as a maximum critical field μ0Hc2=(13.8±0.1) T. To investigate the impact of spin-orbit interaction in superconductor/ferromagnet heterostructures, we then analyze the magnetization dynamics of both normal state and superconducting TaN/\ch{Ni80Fe20}(Permalloy, Py)-bilayers as a function of temperature using broadband ferromagnetic resonance (bbFMR) spectroscopy. The phase sensitive detection of the microwave transmission signal is used to quantitatively extract the inverse current-induced torques of the bilayers. The results are compared to our previous study on NbN/Py-bilayers. In the normal state of TaN, we detect a positive damping-like current-induced torque σd from the inverse spin Hall effect (iSHE) and a small field-like torque σf attributed to the inverse Rashba-Edelstein effect (iREE) at the TaN/Py-interface. In the superconducting state of TaN, we detect a negative σd attributed to the quasiparticle mediated inverse spin Hall effect (QMiSHE) and the unexpected manifestation of a large positive field-like σf of unknown origin matching our previous results for NbN/Py-bilayers.
@article{arxiv.2102.09018,
title = {Growth optimization of TaN for superconducting spintronics},
author = {Manuel Müller and Raphael Hoepfl and Lukas Liensberger and Stephan Geprägs and Hans Huebl and Mathias Weiler and Rudolf Gross and Matthias Althammer},
journal= {arXiv preprint arXiv:2102.09018},
year = {2021}
}