  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.
