Positive exchange bias in a Ni80Fe20/Ni Fe1−O thin-film bilayer

Abstract We have measured positive exchange bias in a Ni 80 Fe 20 /Ni x Fe 1− x O thin-film nanocrystallite system. A series of solid solution Ni x Fe 1− x O 40 nm thick films capped with 25 nm thick Ni 80 Fe 20 were deposited using a range of %O 2 /Ar bombardment energies (i.e. End-Hall voltages). Proper tuning of the deposition conditions results in a Ni 80 Fe 20 /Ni x Fe 1− x O (30%O 2 /Ar) based bilayer that exhibits a positive exchange bias loop shift of H ex ∼60 Oe at 150 K.