Enhancement of exchange bias in Mn{endash}Ir/Co{endash}Fe based spin valves with an ultrathin Cu underlayer and in situ Mn{endash}Ir surface modification
Enhancement of exchange bias induced at the interface of the antiferromagnetic (AF)/ferromagnetic (F) layers was studied using the bottom {open_quotes}spin-valve films{close_quotes} (SVs) with the Mn{endash}Ir/Co{endash}Fe exchange coupled films. Exchange bias increased using an ultrathin Cu underlayer. Meanwhile, both exchange bias field, H{sub ex}, and blocking temperature, T{sub B}, increased intensively by heating specimens after depositing Mn{endash}Ir film in a high vacuum. These two enhancement effects worked in an additive. As a result, an unidirectional anisotropy constant, J{sub K}, of 0.39 erg/cm2 (H{sub ex} of 1.3 kOe) and T{sub B} of {similar_to}325{degree}C were obtained for the bottom SVs with a total thickness of 233 Aa including an AF layer of 68 Aa Mn{sub 74}Ir{sub 26} and a pinned layer of 20 Aa Co{sub 90}Fe{sub 10}, where the SVs were field annealed at 320{degree}C. A microstructural analysis using x-ray diffraction revealed that H{sub ex} did not depend on the diffraction intensity from Mn{endash}Ir (111) for the SVs with various underlayers, and no remarkable changes occurred in the microstructure of the SVs with the heating treatment in a vacuum. Therefore, the enhancement effects might result from some changes in the microstructure and/or the morphology of the interface of AF/F layers. {copyright} 2001 American Institute of Physics.
- Sponsoring Organization:
- (US)
- OSTI ID:
- 40203815
- Journal Information:
- Journal of Applied Physics, Vol. 89, Issue 11; Other Information: DOI: 10.1063/1.1357146; Othernumber: JAPIAU000089000011006609000001; 273111MMM; PBD: 1 Jun 2001; ISSN 0021-8979
- Publisher:
- The American Physical Society
- Country of Publication:
- United States
- Language:
- English
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