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Lorentz transmission electron microscopy and magnetic force microscopy characterization of NiFe/Al-oxide/Co films
Journal of Applied Physics
  • Andrew C. C. Yu, Tohoku University
  • Chester C.H. Lo, Iowa State University
  • Amanda K. Petford-Long, University of Oxford
  • David C. Jiles, Iowa State University
  • Terunobu Miyazaki, Tohoku University
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Magnetization reversal process of NiFe/Al-oxide/Co junction films was observed directly using Lorentztransmission electron microscopy (LTEM) and magnetic force microscopy(MFM).In situmagnetizing experiments performed in both LTEM and MFM were facilitated by a pair of electromagnets, which were mounted on the sample stages. A two-stage magnetization reversal process for the junction film was clearly observed in LTEM with NiFe magnetization reversed first via domain wall motion followed by Co magnetization reversal via moment rotation and domain wall motion. Reversal mechanism and domain characteristics of the NiFe and Co layers showed very distinctive features. The magnetization curve of the junction filmmeasured using alternating gradient force magnetometry showed a nonzero slope at the antiparallel magnetization configuration region, which implies that magnetization directions of the NiFe and Co layers were not exactly antiparallel due to Co moment rotation existed in that region. After the magnetization reversal of the Co was complete, MFM images revealed some magnetic contrast, which suggests that an out-of-plane magnetization component remained in the Co layer. Such magnetic contrast disappeared at higher magnetic fields when the Co moments further rotated and aligned parallel to the applied field direction.

The following article appeared in Journal of Applied Physics 91 (2002): 780 and may be found at

Copyright 2002 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics.
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American Institute of Physics
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Andrew C. C. Yu, Chester C.H. Lo, Amanda K. Petford-Long, David C. Jiles, et al.. "Lorentz transmission electron microscopy and magnetic force microscopy characterization of NiFe/Al-oxide/Co films" Journal of Applied Physics Vol. 91 Iss. 2 (2002) p. 780 - 784
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