Europhys. Lett., 63 (1) , pp. 132-138 (2003)
Flux-closure-domain states and demagnetizing energy determination in sub-micron size magnetic dotsP.-O. Jubert1, J.-C. Toussaint1, O. Fruchart1, C. Meyer1 and Y. Samson2
1 Laboratoire Louis Néel (CNRS, UPR5051) - BP166, 38042 Grenoble Cedex 9, France
2 DRFMC/SP2M/NM (CEA) - 17 rue des Martyrs, F-38054 Grenoble Cedex 9, France
(Received 21 November 2002; accepted in final form 28 April 2003)
We used single-crystalline dots self-assembled under UHV as a model system to discuss micromagnetic properties of sub-micron size magnetic dots and show what properties may or may not be scaled down from macroscopic samples. Landau and diamond states were identified by MFM and reproduced by simulations. These states are surprisingly well reproduced by the Van den Berg model despite the small dots' size. On the contrary, it is argued theoretically that the usual determination procedure of demagnetizing factors Ni's using initial susceptibility or the over-loop area underestimates the real values of Ni's in sub-micron size dots. This point is confirmed both experimentally and in simulations.
75.75.+a - Magnetic properties of nanostructures.
75.70.Kw - Domain structure (including magnetic bubbles).
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