Issue
EPL
Volume 80, Number 5, December 2007
Article Number 57003
Number of page(s) 4
Section Condensed Matter: Electronic Structure, Electrical, Magnetic and Optical Properties
DOI http://dx.doi.org/10.1209/0295-5075/80/57003
Published online 01 November 2007
EPL, 80 (2007) 57003
DOI: 10.1209/0295-5075/80/57003

On the scaling behaviour of cross-tie domain wall structures in patterned NiFe elements

N. Wiese1, S. McVitie1, J. N. Chapman1, A. Capella-Kort2 and F. Otto2

1  University of Glasgow, Department of Physics and Astronomy - Glasgow G12 8QQ, United Kingdom
2  Universität Bonn, Institute for Applied Mathematics - Wegelerstr. 10, 53115 Bonn, Germany


received 3 August 2007; accepted in final form 9 October 2007; published December 2007
published online 1 November 2007

Abstract
The cross-tie domain wall structure in micrometre and sub-micrometre wide patterned elements of NiFe, and a thickness range of 30 to 70 nm, has been studied by Lorentz microscopy. Whilst the basic geometry of the cross-tie repeat units remains unchanged, their density increases when the cross-tie length is constrained to be smaller than the value associated with a continuous film. This occurs when element widths are sufficiently narrow or when the wall is forced to move close to an edge under the action of an applied field. To a very good approximation the cross-tie density scales with the inverse of the distance between the main wall and the element edge. The experiments show that in confined structures, the wall constantly modifies its form and that the need to generate, and subsequently annihilate, extra vortex/anti-vortex pairs constitutes an additional source of hysteresis.

PACS
75.60.Ch - Domain walls and domain structure.
75.70.-i - Magnetic properties of thin films, surfaces, and interfaces.
75.75.+a - Magnetic properties of nanostructures.

© Europhysics Letters Association 2007