Optimization of spin-triplet supercurrent in ferromagnetic Josephson   junctions
  In the past year, several groups have observed evidence for long-range spin-triplet supercurrent in Josephson junctions containing ferromagnetic (F) materials. In our work, the spin-triplet pair correlations are created by non-collinear magnetizations between a central Co/Ru/Co "synthetic antiferromagnet" (SAF) and two outer thin F layers. Here we present data showing that the spin-triplet supercurrent is enhanced up to 20 times after our samples are subject to a large in-plane magnetizing field. This surprising result can be explained if the Co/Ru/Co SAF undergoes a "spin-flop" transition, whereby the two Co layer magnetizations end up perpendicular to the magnetizations of the two thin F layers. Direct experimental evidence for the spin-flop transition comes from scanning electron microscopy with polarization analysis and from spin-polarized neutron reflectometry. 
Carolin Klose, Trupti S. Khaire, Yixing Wang, W. P. Pratt, Jr., Norman   O. Birge, B.J. McMorran, T.P. Ginley, J.A. Borchers...
cond-mat.supr-con cond-mat.mes-hall