Ferromagnetic-semiconductor–singlet-(or triplet) superconductor–ferromagnetic-semiconductor systems as possible logic circuits and switches

Abstract

We consider thin superconducting (S) films of thickness d ≪ ξ 0 , sandwiched between two ferromagnetic semiconducting insulators (F I) with differently orientated magnetizations -the F I − S − F I system. We calculate the dependence of the superconducting critical temperature on the orientation of the magnetization in the insulators and on the thickness of the superconducting film. The calculations are done for singlet as well as triplet superconductors. In the singlet case T c depends on the relative orientation of the left and right magnetization only, while in the triplet case T c depends on the absolute orientation of magnetization. The latter property can serve as a kind of spin-spectroscopy of triplet and unconventional superconductors, for instance in resolving the structure of the triplet order parameter in the recently discovered layered superconductor Sr 2 RuO 4 . The possibility of logic circuits and switches, which are based on the F I − S − F I systems with arbitrary orientation of magnetizations in F I films, is analyzed too.

Superconducting Spin Switch with Infinite Magnetoresistance Induced by an Internal Exchange Field

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Odd-frequency superconducting pairing in one-dimensional systems

“…This equal-spin OTE pairing offers an explanation for the observed long-range penetration of Cooper pairs into diffusive F regions [56][57][58][59][60][61][62][63][64][65]. Additionally, a growing body of evidence indicates that such spin-triplet pairs emerge in FS junctions [66][67][68][69][70][71][72][73][74][75][76][77][78][79], including the paramagnetic Meissner effect [27,80,81] and zero-bias peaks [82,83]. These advances in understanding how odd-ω equal-spin triplet pairing emerges in FS junctions are fascinating not just for their fundamental importance in unconventional superconductivity [84][85][86][87] but also for their potential applications in superconducting spintronics [88][89][90][91].…”

Nanoscale ferromagnet-superconductor-ferromagnet switches controlled by magnetization orientation

“…10 An absolute spin-valve effect can occur at spin-active interfaces in which the tunneling current is finite for a range of voltages.…”