Manifestation of New Interference Effects in a Superconductor-Ferromagnet Spin Valve

This is the authors' abstract. We don't add key points for this paper.

Superconductor-ferromagnet ($S/F$) spin valve effect theories based on the $S/F$ proximity phenomenon assume that the superconducting transition temperature Tc of $F1/F2/S$ or $F1/S/F2$ trilayers for parallel magnetizations of the F1 and F2 layers (TcP) are smaller than for the antiparallel orientations (TcAP). Here, we report for CoOₓ/Fe1/Cu/Fe2/In multilayers with varying Fe2-layer thickness the sign-changing oscillating behavior of the spin valve effect ΔTc=TcAP-TcP. We observe the full direct effect with TcAP>TcP for Fe2-layer thickness dFe2<1 nm and the full inverse (TcAP<TcP) effect for dFe2≥1 nm. Interference of Cooper pair wave functions reflected from both surfaces of the Fe2 layer appear as the most probable reason for the observed behavior of ΔTc.