Angular dependence of the superconducting transition temperature in ferromagnet-superconductor-ferromagnet trilayers

The superconducting transition temperature Tc of a ferromagnet (F)-superconductor (S)-ferromagnet trilayer depends on the mutual orientation of the magnetic moments of the F layers. This effect has been previously observed in F/S/F systems as a Tc difference between parallel and antiparallel configurations of the F layers. Here we report measurements of Tc in CuNi/Nb/CuNi trilayers as a function of the angle between the magnetic moments of the CuNi ferromagnets. The observed angular dependence of Tc is in qualitative agreement with a F/S proximity theory that accounts for the odd triplet component of the condensate predicted to arise for noncollinear orientation of the magnetic moments of the F layers.