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TT: Fachverband Tiefe Temperaturen
TT 3: Superconductivity: Properties and Electronic Structure
TT 3.8: Vortrag
Montag, 5. September 2022, 11:30–11:45, H23
Control of the critical temperature of a superconductor/chiral magnet heterostructure — •Julius Grefe1, Jannis Willwater1, Rodrigo de Vasconcellos Lourenço2, Markus Etzkorn2,3, Stefan Süllow1, and Dirk Menzel1,3 — 1IPKM, TU Braunschweig, Germany — 2IAP, TU Braunschweig, Germany — 3LENA, TU Braunschweig, Germany
Recently, theory has predicted that spin valves consisting of a superconducting film and a magnetic substrate exhibiting a non-collinear spin structure can be controlled via the proximity effect by changing the spin orientation of the magnet. The critical temperature Tc of a thin superconducting Nb film on top of a magnetic MnSi substrate is supposed to be altered when the spin helix vector switches from the in-plane to the out-of-plane direction [1]. We have prepared substrates for molecular beam epitaxy from MnSi single crystals. After preparation the surface roughness has been investigated by AFM and TEM and is in the order of 1 nm. Afterwards, a 20 nm superconducting Nb thin film has been deposited on top of the MnSi substrate. In dependence of the orientation of the external magnetic field and, thus, the direction of the spin helix vector in the MnSi substrate, we observe a change of Tc in the Nb film. To distinguish between the influence of the helix on Tc and pure geometry effects, we compare the result with observations on a Nb film deposited on an isostructural but non-magnetic CoSi substrate.
[1] N. G. Pugach et al., Appl. Phys. Lett. 111, 162601 (2017)