MRSEC Participant: Alex Hiller

MRSEC Faculty Advisor: Chris Leighton

Dependence of Exchange Bias on Annealing Time in Ni₅₀Mn₅₀/Ni₈₀Fe₂₀ Thin Film Bilayers

Our research entailed investigating the hysteresis loop, exchange bias and coercivity as a function of annealing time and temperature in NiMn/NiFe, antiferromagnetic (AF)/ferromagnetic (F) bilayers. Bilayers such as these are used in the magnetic recording industry in "state-of-the-art" read heads. Annealing is required to transform the NiMn from the as-deposited non-magnetic face centered cubic (fcc) phase to the AF face centered tetragonal (fct) phase. We have discovered that a balance exists between annealing aggressively (to completely transform the fcc phase to fct) and restricting the growth of an interdiffused layer at the interface.