Abstract
Dot arrays with diameter D = 80-245 nm were made from Co80Pt20 (20 nm) films with a large perpendicular anisotropy energy. Coercivity increases as D decreases, and reaches 7.6 kOe at D = 80 nm. The switching volume for the dot arrays, estimated from the field sweep-rate dependence of the coercivity, was very small in comparison with the dot volume: about 7% of the dot volume when D = 140 nm, for instance. However, the angular dependence coercivity of these dots exibits a typical rotational type of magnetization reversal. Moreover, MFM images revealed that all the dots show a single domain state during the magnetization reversal. Comparison of the coercivity and the anisotropy field suggests that the reversal process starts from a nucleation at the center of the dot followed by a propagation process. This possibility was confirmed by numerical calculation. It was estimated that the switching field distribution, SFD, of dot arrays was mainly due to the distributions of the c-axis of the hcp-CoPt lattice and the dot diameter. Calculated results indicate that the magneto-static coupling between the dot arrays must be a dominant factor in determining the SFD value when the dots are used for patterned media with a recording density of ∼1 Tbits/inch2.
Original language | Undefined |
---|---|
Article number | 10.3379/jmsjmag.30.100 |
Pages (from-to) | 100-107 |
Number of pages | 8 |
Journal | Journal of the Magnetics Society of Japan |
Volume | 30 |
Issue number | 10/2 |
DOIs | |
Publication status | Published - 2006 |
Keywords
- METIS-248226
- EWI-10787
- TST-SMI: Formerly in EWI-SMI
- TST-uSPAM: micro Scanning Probe Array Memory
- IR-61852