We present ferromagnetic Nb/Al2O3/Ni60Cu40/Nb Josephson junctions (SIFS) with
an ultrathin Al2O3 tunnel barrier. The junction fabrication was optimized
regarding junction insulation and homogeneity of current transport. Using
ion-beam-etching and anodic oxidation we defined and insulated the junction
mesas. The additional 2 nm thin Cu layer below the ferromagnetic NiCu (SINFS)
lowered interface roughness and ensured very homogeneous current transport. A
high yield of junctional devices with jc spreads less than 2% was obtained.Comment: 5 pages, 6 figures; VORTEX IV conference contribution; Submitted to
Physica
