Magnetic Anisotropic Dependent Superconductivity in Bilayers of TmIG/NbN

The interplay between superconductors (SC) and magnetic (M) materials has been attractive for decades because of the complexity, rich physics and its potential for application in the field of superconducting spintronics. We explore via transport measurements the proximity effects of an insulating ferrimagnetic thin film (TmIG = Tm3Fe5O12) with critical temperature (TC) of 550K and a perpendicular magnetic anisotropy coupled to a thin film of type-II superconductor NbN with a TC = 10.5 K . The thin film hybrid structure sputter grown in a UHV system on a GGG(111) substrate is TmIG(20 nm)/NbN(20 nm)/AlN(5 nm). The magnetic behavior was characterized using VSM and ferromagnetic resonance. The transport measurements were performed at different temperatures as a function of angle of the applied magnetic field. The results show the superconducting state dependence on the magnetic anisotropy of the TmIG film: remarkably, the superconducting state is intact with a perpendicular field applied to the film plane, whereas it is destroyed for in-plane fields. This fortifies the complex physics of the SC/M interface while contributing towards a better understanding on the proximity magnetic effects on the fundamental properties of SC thin films, which will be discussed in the talk. *This work was supported by ARO (W911NF-20-2-0061 and DURIP W911NF-20-1-0074), NSF (DMR 1700137, 2218550), ONR (N00014-16-1-2657, N00014-20-1-2306), Center for Integrated Quantum Materials (NSF DMR-1231319), the Brazilian National Institute of Science and Technology of Spintronics and Advanced Magnetic Nanostructures (INCT-SpinNanoMag), and the Brazilian agencies CAPES, FACEPE and CNPq.