Role of canting and depleted-triplet minima in superconducting spin valve structures

Abstract

The trilayer and pentalayer spin valve structures are revisited to determine the behavior of pair correlations and Josephson current when the magnetic layers are canted at arbitrary angle. The two systems display markedly different behaviors in the center magnetic layer. While the trilayer generates a triplet component that is weakly affected by canting, the pentalayer tunes in singlet pair correlations depending heavily on canting. We also show that a minimum with depleted m = ±1 triplet components, rather than a 0 − π transition, may be observed in the current profile Ic(dF ) of a trilayer spin valve. The depleted-triplet minimum (DTM) is directly attributable to a decrease of m = ±1 triplet correlations with increased thickness of the central ferromagnet, accompanied by a hidden, simultaneous sign change of the Gor'kov functions contributed from the left and right superconductors. We introduce a toy model for superconducting-magnetic proximity systems to better illuminate the behavior of individual components of the Gor'kov function and compare with a full numerical calculation. arXiv:1802.08196v1 [cond-mat.supr-con]

Superconducting spin valve under magnonic control

“…Nevertheless, the improvement and optimization of SSVs still remains both a theoretical and experimental challenge [32][33][34][35][36][37][38]. The possible ways to improve the SSV properties call for the optimization of the structures, via their technology of preparation, quality of interfaces, and choice of materials, including strong, half-metallic, and insulating ferromagnets.…”