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Depth-Dependent Magnetization Profiles of Hybrid Exchange Springs

T. N. Anh Nguyen1,2,*, R. Knut3, V. Fallahi4, S. Chung1,5, Q. Tuan Le1, S. M. Mohseni1,6, O. Karis3, S. Peredkov7, R. K. Dumas5 et al.

Casey W. Miller8 and J. Åkerman1,5,9

  • 1Materials and Nano Physics, School of ICT, Royal Institute of Technology, Electrum 229, 164 40 Kista, Sweden
  • 2Spintronics Research Group, Laboratory for Nanotechnology, Vietnam National University-Ho Chi Minh City, Ho Chi Minh City, Vietnam
  • 3Department of Physics and Astronomy, Uppsala University, Box 516, 75120, Sweden
  • 4Faculty of Physics, Amirkabir University of Technology, Hafez Avenue, 1591634311 Tehran, Iran
  • 5Department of Physics, University of Gothenburg, 412 96 Gothenburg, Sweden
  • 6Department of Physics, Shahid Beheshti University, Tehran, Iran
  • 7Max-lab, Lund University, Box 118, 22100 Lund, Sweden
  • 8School of Chemistry and Materials Science, Rochester Institute of Technology, 85 Lomb Memorial Drive, Rochester, New York 14623, USA
  • 9NanOsc AB, Electrum 205, 164 40 Kista, Sweden

  • *To whom correspondence should be addressed. anhntn@kth.se
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Phys. Rev. Applied 2, 044014 – Published 24 October, 2014

DOI: https://doi.org/10.1103/PhysRevApplied.2.044014

Abstract

We report on the magnetization depth profile of a hybrid exchange-spring system in which a Co/Pd multilayer with perpendicular anisotropy is coupled to a CoFeB thin film with in-plane anisotropy. The competition between these two orthogonal anisotropies promotes a strong depth dependence of the magnetization orientation. The angle of the magnetization vector is sensitive both to the strength of the individual anisotropies and to the local exchange constant and is thus tunable by changing the thickness of the CoFeB layer and by substituting Ni for Pd in one layer of the Co/Pd stack. The resulting magnetic depth profiles are directly probed by element-specific x-ray magnetic circular dichroism of the Fe and Ni layers located at different average depths. The experimental results are corroborated by micromagnetic simulations.

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Phys. Rev. Applied 2, 044014– Published 24 October, 2014
  • Received 28 August 2014

© 2014 American Physical Society

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