Pixelated detectors and improved efficiency for magnetic imaging in STEM differential phase contrast

Krajnak, M., McGrouther, D. , Maneuski, D., O'Shea, V. and McVitie, S. (2016) Pixelated detectors and improved efficiency for magnetic imaging in STEM differential phase contrast. Ultramicroscopy, 165, pp. 42-50. (doi: 10.1016/j.ultramic.2016.03.006)

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The application of differential phase contrast imaging to the study of polycrystalline magnetic thin films and nanostructures has been hampered by the strong diffraction contrast resulting from the granular structure of the materials. In this paper we demonstrate how a pixelated detector has been used to detect the bright field disk in aberration corrected scanning transmission electron microscopy (STEM) and subsequent processing of the acquired data allows efficient enhancement of the magnetic contrast in the resulting images. Initial results from a charged coupled device (CCD) camera demonstrate the highly efficient nature of this improvement over previous methods. Further hardware development with the use of a direct radiation detector, the Medipix3, also shows the possibilities where the reduction in collection time is more than an order of magnitude compared to the CCD. We show that this allows subpixel measurement of the beam deflection due to the magnetic induction. While the detection and processing is data intensive we have demonstrated highly efficient DPC imaging whereby pixel by pixel interpretation of the induction variation is realised with great potential for nanomagnetic imaging.

Item Type:Articles
Additional Information:Work funded by RCUK grants (EPRSC grant numbers EP/I013520 and EP/I011668/1).
Glasgow Author(s) Enlighten ID:McVitie, Professor Stephen and Maneuski, Dr Dima and McGrouther, Dr Damien and O'Shea, Professor Val
Authors: Krajnak, M., McGrouther, D., Maneuski, D., O'Shea, V., and McVitie, S.
College/School:College of Science and Engineering > School of Physics and Astronomy
Journal Name:Ultramicroscopy
ISSN (Online):1879-2723
Published Online:07 April 2016
Copyright Holders:Copyright © 2016 The Authors
First Published:First published in Ultramicroscopy 165:42-50
Publisher Policy:Reproduced under a Creative Commons License

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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
547981Current-Driven Domain Wall Motion in Multilayer NanowiresStephen McVitieEngineering & Physical Sciences Research Council (EPSRC)EP/I013520/1P&A - PHYSICS & ASTRONOMY