  Josephson junctions containing three ferromagnetic layers with non-collinear
magnetizations between adjacent layers carry spin-triplet supercurrent under
certain conditions. The signature of the spin-triplet supercurrent is a
relatively slow decay of the maximum supercurrent as a function of the
thickness of the middle ferromagnetic layer. In this work we focus on junctions
where the middle magnetic layer is a [Co/Pd]$_N$ multilayer with perpendicular
magnetic anisotropy (PMA), while the outer two layers have in-plane anisotropy.
We compare junctions where the middle PMA layer is or is not configured as a
synthetic antiferromagnet (PMA-SAF). We find that the supercurrent decays much
more rapidly with increasing the number $N$ of [Co/Pd] bilayers in the PMA-SAF
junctions compared to the PMA junctions. Similar behavior is observed in
junctions containing [Co/Ni]$_N$ PMA multilayers. We model that behavior by
assuming that each Co/Pd or Co/Ni interface acts as a partial spin filter, so
that the spin-triplet supercurrent in the PMA junctions becomes more strongly
spin-polarized as $N$ increases while the supercurrent in the PMA-SAF junctions
is suppressed with increasing $N$. We also address a question raised in a
previous work regarding how much spin-singlet supercurrent is transmitted
through our nominally spin-triplet junctions. We do that by comparing
spin-triplet junctions with similar junctions where the order of the magnetic
layers has been shuffled. The results of this work are expected to be helpful
in designing spin-triplet Josephson junctions for use in cryogenic memory.
