Exchange enhancement and thermal anneal in Mn{sub 76}Ir{sub 24} bottom-pinned spin valves
Exchange enhancement through thermal anneal in bottom-pinned Mn{sub 76}Ir{sub 24} spin valves is investigated. Samples were fabricated by ion beam deposition (IBD), post-annealed in vacuum (10{sup {minus}6}Torr) at 270{degree}C for 10 min, then cooled in a 3 kOe applied field. For a bilayer structure, glass/Ta 40 Aa/NiFe 30 Aa/MnIr 60 Aa/CoFe 25 Aa/Ta 40 Aa, the exchange field (H{sub ex}) reaches 1148 Oe (J{sub ex}=0.4erg/cm{sup 2}) after anneal. X-ray diffraction (XRD) analysis shows strong enhancement of {l_angle}111{r_angle} texture upon anneal, while grain size obtained from XRD and transmission electron microscopy for as-deposited and annealed states shows no major change. With increasing MnIr thickness, the exchange field decreases, and blocking temperature (T{sub b}) increases, reaching 295{degree}C for t{sub MnIr}=180Aa. Spin valves built with the same exchange bilayer (Ta 20 Aa/NiFe 30 Aa/MnIr 60 Aa/CoFe 25 Aa/Cu 22 Aa/CoFe 20 Aa/NiFe 40 Aa/Ta 40 Aa) show H{sub ex}=855Oe (J{sub ex}=0.3erg/cm{sup 2}) and magnetoresistance (MR)=7.1%. The incorporation of nano-oxide layers in spin valves increases the MR signal to 11%. No signal degradation is found in these specular structures for anneals up to 310{degree}C. {copyright} 2001 American Institute of Physics.
- Sponsoring Organization:
- (US)
- OSTI ID:
- 40203907
- Journal Information:
- Journal of Applied Physics, Vol. 89, Issue 11; Other Information: DOI: 10.1063/1.1354581; Othernumber: JAPIAU000089000011006904000001; 153111MMM; PBD: 1 Jun 2001; ISSN 0021-8979
- Publisher:
- The American Physical Society
- Country of Publication:
- United States
- Language:
- English
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