Control of Spin-Triplet Josephson Junctions with Perpendicular Anisotropy

We present recent work on S/F'/F/F''/S Josephson Junctions with the magnetic multilayer Ni/[Co/Ni]$_n$ as the central F layer [1]. This multilayer possesses strong intrinsic perpendicular (out-of-plane) anisotropy at Co and Ni thicknesses of a few monolayers. If a hard ferromagnet is used for F', and a softer ferromagnet is used for F'', both with magnetizations in plane, the direction of the F'' layer's magnetization is predicted to control the state of the junction [2]. We are fabricating such junctions with the goal of controllably switching the junction between the $0$ and $\pi$ states. By integrating these junctions in a SQUID device, a measurement of the $0$and $\pi$ state of the junction can be performed. We will report on our progress.\\ \\ $[$1$]$ E.C. Gingrich, P. Quarterman, Y. Wang, R. Loloee, W.P. Pratt, and N.O. Birge, arXiv:1208.3118v1.\\ $[$2$]$ A.F. Volkov, F.S. Bergeret, and K.B. Efetov, Phys. Rev. Lett. \textbf{90}, 117006 (2003).