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Magnetic ground state of single and coupled permalloy rectangles
S Hankemeier1, R Frömter, N Mikuszeit
1Universität Hamburg, Institut für Angewandte Physik, Jungiusstrasse 11, D-20355 Hamburg, Germany. shankeme@physnet.uni-hamburg.de
Physical Review Letters
|November 13, 2009
Summary
Researchers studied magnetic domains in Permalloy rectangles, finding unexpected coupling between them. This magnetic coupling, forming a common chirality pattern, is influenced by shape and spacing, contrary to prior expectations.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Nanotechnology
Background:
- Permalloy rectangles exhibit complex magnetic domain structures.
- Flux-closure domain configurations are common in such geometries.
- Understanding inter-element coupling is crucial for magnetic device design.
Purpose of the Study:
- To investigate the magnetic domain structure in arrays of Permalloy rectangles.
- To explore the coupling mechanisms between adjacent rectangles in a flux-closure Landau state.
- To determine the influence of rectangle spacing and shape on magnetic interactions.
Main Methods:
- Scanning electron microscopy with polarization analysis (SEMPA) was employed to visualize domain structures.
- Micromagnetic simulations were performed to model and understand the observed magnetic behavior.
- Arrays with varying rectangle separations were systematically studied.
Main Results:
- Rectangles in the flux-closure Landau state exhibit significant magnetic coupling.
- A common chirality pattern was observed across the array, indicating correlated magnetization.
- This coupling arises from stray fields generated by minor magnetization alignment variations.
- The degree of coupling is sensitive to the precise shape and separation of the rectangles.
Conclusions:
- Contrary to general expectations, significant coupling exists between Permalloy rectangles in a flux-closure state.
- Stray field interactions, influenced by geometric parameters, dictate the collective magnetic behavior.
- The findings have implications for designing nanoscale magnetic arrays and memory devices.
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