Size effect on magnetoresistance of ring-shaped ferromagnetic elements
Abstract
Generally, the geometry determines that which kind of magnetization configuration and switching mechanism may occur in the patterned magnetic thin films. Recently, many investigations have been carried out on microstructured elements with simple geometries such as squares, disks, rectangles, and rings. Among these various shapes of magnetic elements, the ring-shaped element has become a promising candidate for the magnetic random access memory or sensor devices. In addition, the application of such elements requires the simplest, fastest, and most reproducible switching mechanism. In order to explore the magnetization switching mechanism, some techniques, such as MOKE, VSM, and SHPM, have been vigorously adopted. Herein, the magnetization switching behavior of Permalloy ring elements as a function of ring diameter and film thickness by magnetoresistance measurement will be presented. The Permalloy ring elements, with diameters of 2-5 micrometers and thicknesses of 14 - 66 nm, were fabricated by electron beam lithography through a lift-off process. To conclude, the switching field for the transition from the vortex state to the onion state increases with decreasing diameter. Furthermore, as the film thickness is less/more than 53 nm the switching field increases/decreases with increasing film thickness.
- Publication:
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APS March Meeting Abstracts
- Pub Date:
- March 2004
- Bibcode:
- 2004APS..MAR.C1084C