| AVS 55th International Symposium & Exhibition | |
| Magnetic Interfaces and Nanostructures | Tuesday Sessions |
| Session MI+NC-TuA |
| Session: | Magnetic Microscopy and Magnetization Dynamics |
| Presenter: | D.P. Pappas, National Institute of Standards and Technology |
| Authors: | D.P. Pappas, National Institute of Standards and Technology L. Yuan, National Institute of Standards and Technology F.C.S. da Silva, National Institute of Standards and Technology A. Davydov, National Institute of Standards and Technology |
| Correspondent: | Click to Email |
Co nanocrystals were prepared and MFM measurements revealed the dependence of the magnetization on the shapes of the nano-crystals. The nanodots were formed by depositing a 10 nm film of Co onto a c-axis oriented sapphire crystal, which was then annealed to 1000 C. Nanocrystals formed with average size of about 500 nm, with a variety of shapes. From the shapes, it is apparent that some random nucleation occured. The nanocrystals fall into two categories, hexagonal shaped and rectangular. The MFM images of the first type showed that the magnetization formed a central vortex core, with a magnetic reconstructions of either 3-fold or 6-fold symmetry around the core. The latter particles showed a maze-like magnetic configuration. These studies show that the strong uniaxial anisotropy persists in these particles, and the magnetic configuration is strongly dependent on the shape of the particles. Moreover, the circular dots have a strong tendency to form highly symmetric patterns.