Thermal stability of Ta-pinned spin valves
It has recently been found that large uniaxial anisotropy fields in excess of 120 kA/m (1500 Oe) can be created in thin (3{endash}5 nm) films of Co by obliquely sputtered Ta underlayers. This anisotropy can be used to pin the bottom film of a spin valve while having only a modest effect on the top {open_quotes}free{close_quotes} film, separated by a 2.5 nm Cu spacer layer. This article describes measurements of thermal stability in these Ta-pinned spin valves. Using room temperature giant magnetoresistance (GMR) as a measure, we find that the structure is stable under cumulative 20 min anneals at 25{degree}C intervals up to 300{degree}C; GMR decreases to zero upon further anneals up to 450{degree}C. Measurements taken at elevated temperatures reveal that GMR decreases linearly with temperature, extrapolating to zero at approximately 425{degree}C, while the anisotropy field is much less temperature dependent, remaining nearly constant up to 150{degree}C and gradually decreasing to 50% of its room temperature value at 325{degree}C. {copyright} 2001 American Institute of Physics.
- Sponsoring Organization:
- (US)
- OSTI ID:
- 40203885
- Journal Information:
- Journal of Applied Physics, Vol. 89, Issue 11; Other Information: DOI: 10.1063/1.1357147; Othernumber: JAPIAU000089000011006825000001; 274111MMM; PBD: 1 Jun 2001; ISSN 0021-8979
- Publisher:
- The American Physical Society
- Country of Publication:
- United States
- Language:
- English
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