Three-dimensional magnetization profile and multiaxes exchange bias in Co antidot arrays

Farid Fettar (1) , Laurent Cagnon (2) , Nicolas Rougemaille (2)

1 NEEL - SIN - Surfaces, Interfaces et Nanostructures
2 NEEL - MNM - Micro et NanoMagnétisme

Magnetic properties of Cu/Co/Cu trilayers deposited on nanoporous alumina membranes are investigated using a superconducting quantum interference device. Hysteresis loops of the resulting Co antidot arrays show two-step magnetization reversal. Due to oxidation when samples are exposed to air, CoO forms and exchange bias is observed, whether the cooling field is applied within or perpendicular to the surface plane. In the former case, the exchange bias changes sign close to the blocking temperature of Co/CoO. We attribute these effects to the local, crescent shape of the Co films induced by the surface morphology of the membranes, which leads to a three-dimensional magnetization distribution.

Mots clés: cobalt; copper; exchange interactions (electron); ferromagnetic materials; magnetic hysteresis; magnetic multilayers; magnetic thin films; surface morphology; Magnetic properties of monolayers and thin films; Other ferromagnetic metals and alloys; Exchange and superexchange interactions; Magnetic properties of interfaces; Magnetization curves hysteresis Barkhausen and related effects

Domaines: Science des matériaux [cond-mat.mtrl-sci]

Farid Fettar, Laurent Cagnon, Nicolas Rougemaille. Three-dimensional magnetization profile and multiaxes exchange bias in Co antidot arrays. Applied Physics Letters, 2010, 97, pp.2502. ⟨10.1063/1.3512864⟩. ⟨hal-00997638⟩