Superconductors permit the flow of charge in the absence of Ohmic dissipation, but since the Cooper pairs of electrons have antiparallel spins, charge currents cannot carry a net spin. Furthermore, since such singlet pairs are easily disrupted by magnetism, the coupling of superconductivity and ferromagnetism might appear useless for applications in spintronics. However, during the past few years a series of discoveries have shown that, not only can magnetism and superconductivity be made to cooperate, but in carefully engineered superconductor/magnet systems new functionality can be created in which spin, charge and superconducting phase coherence can work together (1). By combining these different degrees of freedom a whole new spectrum of exciting predictions is waiting to be explored, and the field of superconducting spintronics has emerged.
In the first part of this talk I will overview the state-of-the-art in superconducting spintronics with an emphasis on the generation of spin-polarized (spin-triplet) Cooper pairs at magnetically inhomogeneous superconductor / magnet interfaces. In the second part, I will discuss my group’s recent results, which include manipulation of superconductivity in superconducting spin-valves with half-metallic ferromagnets and density of state measurements on both sides of superconductor / half-metallic ferromagnetic interfaces (2,3).
1. J. Linder and J.W.A. Robinson. Nature Physics 11, 307 (2015).
2. Y. Kalcheim et al. Phys. Rev B (Rapid) 89, 180506 (2014).
3. Y Kalcheim, et al Phys. Rev. B (Rapid) 92, 060501 (2015).