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Title: 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

Abstract

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.

Authors:
; ; ; ;  [1];  [2]
  1. Department of Physics and Astronomy, University of Manitoba, Winnipeg, Manitoba, R3T 2N2 (Canada)
  2. (China)
Publication Date:
OSTI Identifier:
20788109
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 99; Journal Issue: 8; Other Information: DOI: 10.1063/1.2162034; (c) 2006 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 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

Citation Formats

Lierop, J. van, Lin, K.-W., Ouyang, H., Tzeng, Y.-M., Guo, Z.-Y., and Department of Materials Engineering, National Chung Hsing University, Taichung 402, Taiwan. 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. United States: N. p., 2006. Web. doi:10.1063/1.2162034.
Lierop, J. van, Lin, K.-W., Ouyang, H., Tzeng, Y.-M., Guo, Z.-Y., & Department of Materials Engineering, National Chung Hsing University, Taichung 402, Taiwan. 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. United States. doi:10.1063/1.2162034.
Lierop, J. van, Lin, K.-W., Ouyang, H., Tzeng, Y.-M., Guo, Z.-Y., and Department of Materials Engineering, National Chung Hsing University, Taichung 402, Taiwan. Sat . "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". United States. doi:10.1063/1.2162034.
@article{osti_20788109,
title = {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},
author = {Lierop, J. van and Lin, K.-W. and Ouyang, H. and Tzeng, Y.-M. and Guo, Z.-Y. and Department of Materials Engineering, National Chung Hsing University, Taichung 402, Taiwan},
abstractNote = {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.},
doi = {10.1063/1.2162034},
journal = {Journal of Applied Physics},
number = 8,
volume = 99,
place = {United States},
year = {Sat Apr 15 00:00:00 EDT 2006},
month = {Sat Apr 15 00:00:00 EDT 2006}
}