Magnetization reversal studies of continuous and patterned exchange biased NiFe/FeMn thin films

In this article we present a detailed investigation of the structural and magnetic properties of exchange biased NiFe (ferromagnet)/FeMn (antiferromagnet) thin films. The influence of the shape anisotropy on exchange bias and the magnetization reversal mechanism in a sample with patterned lines is compared with a continuous two-dimensional reference sample. Polarized neutron reflectivity (PNR) is employed to study the magnetization reversal by analyzing the spin-flip and non-spin-flip reflectivities. PNR measurements show that the magnetization reversal in the reference two-dimensional film and patterned lines is by domain wall motion rather than coherent rotation of magnetization.