Magnetic hardening of Fe30Co70 nanowires

3d transition metal-based magnetic nanowires (NWs) are currently considered as potential candidates for alternative rare-earth-free alloys as novel permanent magnets. Here, we report on the magnetic hardening of Fe30Co70 nanowires in anodic aluminium oxide templates with diameters of 20 nm and 40 nm...

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Bibliographic Details
Published in:Nanotechnology 2015-10, Vol.26 (41), p.415704-415704
Main Authors: Viñas, Sara Liébana, Salikhov, Ruslan, Bran, Cristina, Palmero, Ester M, Vazquez, Manuel, Arvan, Behnaz, Yao, Xiang, Toson, Peter, Fidler, Josef, Spasova, Marina, Wiedwald, Ulf, Farle, Michael
Format: Article
Language:English
Subjects:
domain wall motion
exchange coupling
magnetic anisotropy
magnetic nanowires
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Summary:3d transition metal-based magnetic nanowires (NWs) are currently considered as potential candidates for alternative rare-earth-free alloys as novel permanent magnets. Here, we report on the magnetic hardening of Fe30Co70 nanowires in anodic aluminium oxide templates with diameters of 20 nm and 40 nm (length 6 m and 7.5 m, respectively) by means of magnetic pinning at the tips of the NWs. We observe that a 3-4 nm naturally formed ferrimagnetic FeCo oxide layer covering the tip of the FeCo NW increases the coercive field by 20%, indicating that domain wall nucleation starts at the tip of the magnetic NW. Ferromagnetic resonance (FMR) measurements were used to quantify the magnetic uniaxial anisotropy energy of the samples. Micromagnetic simulations support our experimental findings, showing that the increase of the coercive field can be achieved by controlling domain wall nucleation using magnetic materials with antiferromagnetic exchange coupling, i.e. antiferromagnets or ferrimagnets, as a capping layer at the nanowire tips.
ISSN:0957-4484
1361-6528
DOI:10.1088/0957-4484/26/41/415704