Lawrence Berkeley National Laboratory
Interparticle magnetic correlations in dense Co nanoparticle
- Author(s): Kortright, Jeffrey B.
- Hellwig, Olav
- Sun, Shouheng
- Fullerton, Eric E.
- et al.
Resonant magnetic x-ray scattering from dense self-assemblies of 9-nm diameter epsilon-Co and hcp-Co particles is reported. For lower anisotropy epsilon-Co we find remanent magnetic scattering that is significantly enhanced, indicating preferred inter-particle moment orientations of both antiferromagnetic and ferromagnetic character. This interaction-mediated collective behavior is consistent with dipolar fields and exists well above the isolated particles blocking temperature where thermal activation is operative, suggesting that magnetostatic super-spin waves exist in such systems.