Effect of Ir-Mn composition on exchange bias and thermal stability of spin valves with nano-oxide layers
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100080 (China)
- Department of Materials Physics, University of Science and Technology Beijing, Beijing 100083 (China)
The Ir-Mn bottom-pinned spin valves with nano-oxide layers (NOLs), Ta/Ni{sub 81}Fe{sub 19}/Ir-Mn/Co{sub 90}Fe{sub 10}/NOL/Co{sub 90}Fe{sub 10}/Cu/Co{sub 90}Fe{sub 10}/NOL/Ta, were fabricated by dc magnetron sputtering. The magnetoresistance (MR), magnetization, and exchange bias have been studied as a function of Ir-Mn composition and annealing temperature. It was observed that the spin valves with the Ir-Mn layer containing relatively low Mn content (58.9-72.4 at. % Mn) show the best thermal endurance. For these samples, the Mn diffusion is effectively hampered by the NOL with a large MR value of about 12.5% even after annealing at 300 deg. C. On the other hand, the exchange bias field of the pinned CoFe layer shows a maximum at Mn content of about 72.4 at. %, which is different from the widely adopted composition, Ir-80 at. % Mn, optimized from the top-pinned NiFe/Ir-Mn system. Moreover, the blocking temperature of the Ir-Mn/CoFe system with 72.4 at. % Mn is higher than that with 80.6 at. % Mn. The present results suggest that the Ir-Mn/CoFe pinning system with Mn content at about 72% renders the most favorable exchange bias and the best thermal stability for the bottom-pinned specular spin valves.
- OSTI ID:
- 21137246
- Journal Information:
- Journal of Applied Physics, Vol. 103, Issue 9; Other Information: DOI: 10.1063/1.2917396; (c) 2008 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
- Country of Publication:
- United States
- Language:
- English
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