  In this work, we show fundamental low temperature (T) magnetic and Ic
responses of a magnetic Josephson Junction (MJJ) S/F/S heterostructure - Nb/
Co56Fe24B20 /Nb. The ultra-thin Co56Fe24B20 (CFB) films (0.6-1.3 nm) were
deposited onto two separate buffer layers: 150 nm Nb/5 nm Cu and 150 nm Nb/ (1
nm Cu/0.5 nm Nb)6/1 nm Cu. Both film sets were capped with 5 nm Cu/50 nm Nb.
Magnetic results show reduced switching distributions in patterned arrays
measured at near liquid Helium temperature (~ 10 K), with the incorporation of
the (1 nm Cu/0.5 nm Nb)6/1 nm multilayer. In electrical devices, the critical
current (Ic) through the CFB layer decays exponentially with increasing
ferromagnetic layer thickness and shows a dip in Ic at 0.8 nm, characteristic
of a change in the equilibrium Josephson phase in an S/F/S structure.
