Abstract
A study of the magnetization reversal process of NiFe elliptical rings has been made as a function of ring size and ring orientation with respect to the applied field. The long axis of the rings ranged from 600 nm to 6 μm and the ring width and thickness were fixed at ∼220 and 20 nm, respectively. The magnetization reversal mechanism was characterized using Lorentz transmission electron microscopy as a function of the angle between the long axis of the ellipse and the applied field. A decrease in the range of stability of the intermediate vortex state with increasing angle between the long axis and the applied field was observed. The structure of the remanent domain walls was dependent on the size of the ring, and a phase diagram of domain-wall type as a function of ring geometry calculated from Landau-Lifshitz-Gilbert simulations is presented for comparison with the experimental data.
| Original language | English (US) |
|---|---|
| Article number | 08H304 |
| Journal | Journal of Applied Physics |
| Volume | 99 |
| Issue number | 8 |
| DOIs | |
| State | Published - 2006 |
Funding
Two of the authors (C.A.R. and F.J.C.) acknowledge the support of the National Science Foundation. Another author (T.B.) acknowledges support from the Engineering and Physical Sciences Research Council. Table I. Sample identifications. Sample ID Long axis ( μ m ) Short axis ( μ m ) Width (nm) A ratio 1 6.55 ± 0.25 4.43 ± 0.17 225 ± 14 1.5 2 4.37 ± 0.11 2.26 ± 0.15 219 ± 8 1.9 3 1.19 ± 0.08 0.78 ± 0.15 221 ± 14 1.5 4 0.62 ± 0.10 0.48 ± 0.10 200 ± 20 1.3 FIG. 1. Vortex stability range as a function of the angle between the applied field and the ring long axis for the ring with 1 - μ m - long axis. FIG. 2. Schematic of domain-wall configurations observed in magnetic rings (a) vortex type, (b) transverse wall, corresponding experimental images (c) and (d) calculated by solving the TIE equation and differentiating the phase along the direction perpendicular to the white arrows to give B x and B y induction maps. Induction maps produced by LLG simulations are included for comparison [(e) and (f)]. FIG. 3. Phase diagram for domain-wall type as a function of ring dimensions. Hollow symbols represent the simulated images for rings of 20 - nm - thick and 230 nm diameter, while solid points indicate the experimental results.
ASJC Scopus subject areas
- General Physics and Astronomy