Magnetoanisotropic Josephson effect in superconductor/ferromagnet/superconductor (S/F/S) junctions

Heterostructures combining two nominally antagonistic states---superconductivity and ferromagnetism---are promising systems for future spintronic devices. Perhaps most striking in S/F/S Josephson junctions is the existence of $\pi$-states, in which an additional $\pi$-shift to the superconducting phase difference reverses the Josephson current flow compared to the usual (0-) state. Due to structure inversion asymmetry, interfacial spin-orbit fields invariably emerge in heterojunctions. By performing numerical calculations on S/F/S model junctions in the presence of interfacial Rashba and Dresselhaus spin-orbit fields, we study the unique signatures of the interplay of ferromagnetism and the spin-orbit fields in the Josephson current flow.\footnote{arXiv:1608.01218} We find that the Rashba fields can not only significantly enhance the Josephson current, but even induce transitions from 0- to $\pi$-states. As a clear indication for the spin-orbit fields, we predict marked magnetoanisotropies in the Josephson current. These anisotropies are huge compared to tunneling anisotropic magnetoresistance in normal-state junctions, particularly close to 0-$\pi$ transitions. Finally, we show that 0-$\pi$ transitions can also be manipulated by solely rotating the magnetization in the F layer.