Anomalous positive exchange bias in Ni{sub 80}Fe{sub 20}/Ni{sub x}Fe{sub 1-x}O thin-film bilayers induced by ion-beam deposition effects
- Department of Physics and Astronomy, University of Manitoba, Winnipeg, Manitoba, R3T 2N2 (Canada)
We present results on a Ni{sub 80}Fe{sub 20}/Ni{sub x}Fe{sub 1-x}O thin-film bilayer that shows a positive exchange bias loop shift of {approx}90 Oe at 10 K under zero-field-cooled conditions. Zero-field-cooled and field-cooled hysteresis loops were double shifted at temperatures below 200 K. This behavior is due to the presence of a range of antiferromagnetic crystallite sizes in addition to multiple magnetic phases (e.g., FeO, Fe{sub 2}O{sub 3}, and NiO). Furthermore, the positive exchange bias loop shift decreases linearly with increasing temperature, with a compensation temperature T{sub comp}{approx}220 K, after which negative exchange bias is measured. This temperature dependence of the exchange bias reflects the competition between the Ni{sub 80}Fe{sub 20} ferromagnet and antiferromagnetic Fe oxide and NiO phases as wel as a range of local blocking temperatures. We attribute the appearance of a positive exchange bias loop shift at low temperatures to temperature-dependent changes in the interfacial pinning and exchange coupling due to a complex Ni{sub x}Fe{sub 1-x}O structure from energetic ion-beam bombardment effects during the film deposition.
- OSTI ID:
- 20788109
- Journal Information:
- Journal of Applied Physics, Vol. 99, Issue 8; Other Information: DOI: 10.1063/1.2162034; (c) 2006 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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Related Subjects
ANTIFERROMAGNETIC MATERIALS
ANTIFERROMAGNETISM
DEPOSITION
EXCHANGE INTERACTIONS
FERROMAGNETIC MATERIALS
HYSTERESIS
ION BEAMS
IRON ALLOYS
IRON OXIDES
NICKEL ALLOYS
NICKEL OXIDES
TAIL IONS
TEMPERATURE DEPENDENCE
TEMPERATURE RANGE 0000-0013 K
TEMPERATURE RANGE 0065-0273 K
THIN FILMS