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arXiv · 1504.06716

Magnetic phase transitions in Ta/CoFeB/MgO multilayers

I. Barsukov·Yu Fu·C. Safranski·Y. -J. Chen·B. Youngblood·A. M. Gonçalves·M. Spasova·M. Farle·J. A. Katine·C. C. Kuo·I. N. Krivorotov
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Abstract

We study thin films and magnetic tunnel junction nanopillars based on Ta/Co$_{20}$Fe$_{60}$B$_{20}$/MgO multilayers by electrical transport and magnetometry measurements. These measurements suggest that an ultrathin magnetic oxide layer forms at the Co$_{20}$Fe$_{60}$B$_{20}$/MgO interface. At approximately 160 K, the oxide undergoes a phase transition from an insulating antiferromagnet at low temperatures to a conductive weak ferromagnet at high temperatures. This interfacial magnetic oxide is expected to have significant impact on the magnetic properties of CoFeB-based multilayers used in spin torque memories.

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I. Barsukov, Yu Fu, C. Safranski, Y. -J. Chen, B. Youngblood, A. M. Gonçalves, M. Spasova, M. Farle, J. A. Katine, C. C. Kuo, I. N. Krivorotov. 2015-04-25. Magnetic phase transitions in Ta/CoFeB/MgO multilayers. https://doi.org/10.1063/1.4921306

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