Flux-closure-domain states and demagnetizing energy determination in sub-micron size magnetic dots

• Published in: Europhysics letters Vol. 63; no. 1; pp. 132 - 138
• Main Authors: Jubert, P.-O, Toussaint, J.-C, Fruchart, O, Meyer, C, Samson, Y
• Format: Journal Article
• Language: English
• Published: Les Ulis IOP Publishing 01.07.2003; EDP Sciences; EDP sciences; European Physical Society / EDP Sciences / Società Italiana di Fisica / IOP Publishing
• Subjects: 75.70.Kw; 75.75.+a; Condensed Matter; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Exact sciences and technology; Magnetic properties and materials; Magnetic properties of monolayers and thin films; Magnetic properties of surface, thin films and multilayers; Other; Physics; Energy levels; Theoretical study; Iron; Self-assembled layers; Landau levels; Magnetic force microscopy; Magnetic susceptibility; Micromagnetism; Monocrystals; Domain structure; Discontinuous metallic thin films; Island structure; Demagnetization; Magnetization reversal
• ISSN: 0295-5075; 1286-4854
• DOI: 10.1209/epl/i2003-00488-0

We used single-crystalline $\chem{Fe}$ 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.