Noncollinear Magnets Based Superconducting Spin Valves
In the original paper the affiliation of A.S. Aladyshkina was indicated incorrectly. The correct affiliations of all authors are as follows:
A.Yu. Aladyshkin., (1) I.M. Nefedov(1), A.S. Aladyshkina(2) and I.A. Shereshevskii(1). (1) Institute for Physics of Microstructures, Russian Academy of Sciences, GSP.105, Nizhny Novgorod 603950, Russia (2) National Research University Higher School of Economics, 25/12 Bolshaja Pecherskaja Ulitsa, Nizhny Novgorod 603155, Russia
We investigate numerically the formation of vortex–antivortex pairs in thin-film superconducting strip in the presence of a straight current-carrying wire, oriented perpendicular to this strip. We demonstrate that the change in the number of the trapped vortices/antivortices inside the strip near the current-carrying wire results in a oscillatory dependence of the critical current Ic on the magnitude of the control current Iw in the wire. We consider the effect of the width of the superconducting strip and the width of the control wire on the period and the amplitude of the dc-Josephson-like oscillations of the critical current.
Using the Usadel equation approach, we have calculated the critical current density in ferromagnetic (F) Josephson junctions of different types containing insulating (I) and normal metal (N) layers in the weak link region. Even a thin additional N layer may change the boundary conditions at the SF or IF interface, where S is a superconducting electrode. We show that inserting an N layer may increase the critical current density Jc and shift the 0- transition to larger or smaller values of the thickness dF of the ferromagnet, depending on the boundary parameters.
The theory and transport measurements are presented on superconducting spin-valve systems, where the controlled non-collinear arrangement of two ferromagnetic Co layers can be used to influence the superconducting state of Nb. We observe a very clear oscillation of the superconducting transition temperature (Tc) with the relative orientation of the two ferromagnetic layers. We report the formation of long-range triplet superconducting correlations (LRTC) according to our theory. Singlet BCS correlations is shown to lead to a weak enhancement of Tc for the anti-parallel configuration of exchange fields, while much larger changes are observed for other configurations, which can be attributed to drainage currents due to LRTC formation.