Jul 23, 2009

Direct evidence of imprinted vortex states in the antiferromagnet of exchange biased microdisks

Josep Nogués, leader of the Magnetic Nanostructures group, together with Pietro Gambardella, leader, and other members of the Atomic Manipulation and Spectroscopy Group, both from CIN2 (ICN-CSIC), have published the paper 'Direct evidence of imprinted vortex states in the antiferromagnet of exchange biased microdisks' on Applied Physics Letters.

The magnetic domain structure of patterned antiferromagnetic/ferromagnetic Ir₂₀Mn₈₀/Ni₈₀Fe₂₀ bilayer microdisk arrays has been investigated using layer-specific polarized x-ray photoemission electron microscopy and magnetic circular dichroism. Magnetic imaging at the Fe and Mn L-edge resonances provided direct evidence of a vortex state imprinted into the antiferromagnet at the interface. The opposite magnetic contrast between the layers indicated a reversed chirality of the imprinted vortex state, and a quantitative analysis of the magnetic moment from the dichroism spectra showed that uncompensated Mn spins equivalent to about 60% of a monolayer of bulk Ir₂₀Mn₈₀ contributed to the imprinted information at the interface.

+ DOI:10.1063/1.3168515