The antiferromagnetic structures of IrMn3 and their influence on exchange-bias

Journal article

We have determined the magnetic structures of single-crystal thin-films of IrMn3 for the crystallographic phases of chemically-ordered L12 and for chemically-disordered face-centred-cubic, which is the phase typically chosen for information-storage devices. For the chemically-ordered L12 thin-film, we find the same triangular magnetic structure as reported for the bulk material. We determine the magnetic structure of the chemically-disordered face-centred-cubic alloy for the first time, which differs from theoretical predictions, with magnetic moments tilted away from the crystal diagonals towards the face-planes. We study the influence of these two antiferromagnetic structures on the exchange-bias properties of an epitaxial body-centred-cubic Fe layer showing that magnetization reversal mechanism and bias-field in the ferromagnetic layer is altered significantly. We report a change of reversal mechanism from in-plane nucleation of 90° domain-walls when coupled to the newly reported cubic structure towards a rotational process, including an out-of-plane magnetization component when coupled to the L12 triangular structure.

Authors: Kohn, A; Kovács, A; Fan, R; McIntyre, G; Ward, R

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: Springer Nature
• Journal: Scientific Reports
• Volume: 3
• Article number: 2412
• Publication date: 2013-08-12
• Acceptance date: 2013-07-23
• DOI: 10.1038/srep02412
• EISSN: 2045-2322
• Language: English
• Keywords: FFR