Simultaneous Measurement of Magnetic Vortex Polarity and Chirality using Scanning Electron Microscopy with Polarization Analysis (SEMPA)

Published

February 16, 2010

Author(s)

Seok-Hwan Chung, Daniel T. Pierce, John Unguris

Abstract

The magnetic vortex structure is an equilibrium configuration frequently found in patterned magnetic nanostructures. It is characterized by an in-plane curling of the magnetization with clockwise or anticlockwise chirality and by an out of plane vortex core that can have a positive or negative polarity. The small size of the vortex core, on the order of 10 nm, makes it technologically interesting, but also difficult to measure or image directly. In this work, we used Scanning Electron Microscopy with Polarization Analysis (SEMPA) to directly image magnetic vortex cores in patterned NiFe/Ta bilayer structures. With SEMPA we can simultaneously measure the in-plane and the out-of-plane component of the surface magnetization and thereby determine both the vortex chirality and the vortex core polarity in a single measurement. Our magnetic simulation of the vortex core, considering only the exchange and magnetostatic energy, is in good agreement with the SEMPA measurement of the magnetization when other experimental factors are taken into account.

Citation

Ultramicroscopy

Volume

110

Issue

3

Pub Type

Journals

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Keywords

magnetic vortex, magnetic vortex core, scanning electron microscopy with polarization analysis (SEMPA), micromagnetic simulation (OOMMF)

Citation

Chung, S. , Pierce, D. and Unguris, J. (2010), Simultaneous Measurement of Magnetic Vortex Polarity and Chirality using Scanning Electron Microscopy with Polarization Analysis (SEMPA), Ultramicroscopy, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=903073 (Accessed March 13, 2025)