Determination of magnetic vortex polarity from a single Lorentz Fresnel image.
Nanoscale confinement of the magnetization in a magnetic element often results in the creation of a vortex structure. The vortex equilibrium state is characterized by the curling of the in-plane magnetization (chirality) and an out-of-plane core magnetization. The polarity of the vortex core can point up or down, independent of the chirality, and, thus, magnetic elements with a vortex core are interesting as four-state logic elements. We present an easy-to-use, quantitative method for the determination of both chirality and polarity from a single Fresnel image. This method offers direct evidence of the three-dimensional structure of a magnetic vortex and has significant advantages over the more complex methods currently in use.
Phatak
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Department of Materials Science and Engineering, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, PA 15213, USA.
Tanase
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M
Petford-Long
A K
AK
De Graef
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M