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Title: Correlation between antiferromagnetic interface coupling and positive exchange bias

Journal Article · · Physical Review. B, Condensed Matter and Materials Physics
 [1];  [2];  [2]
  1. Departament de Fisica, Universitat Autonoma de Barcelona, 08193 Bellaterra, (Spain)
  2. Department of Physics 0319, University of California-San Diego, La Jolla, California 92093-0319 (United States)

The induced moment in antiferromagnetic (AFM)-ferromagnetic (FM) (FeF{sub 2}-Fe and MnF{sub 2}-Fe) bilayers has been studied from the shift along the magnetization axis of the exchange-biased hysteresis loops. The magnetization shift depends strongly on the cooling field and microstructure of the AFM layer. The shift for small cooling fields can be opposite to the cooling field, indicating that, in some cases, the presence of the FM layer induces an antiferromagnetic coupling at the interface. Samples with negative magnetization shifts (antiferromagnetic coupling) exhibit large changes in exchange bias H{sub E} as a function of cooling field and positive exchange bias. Samples with positive magnetization shifts (ferromagnetic coupling) show almost no change in H{sub E} with cooling field and the exchange bias field remains always negative. These results confirm the theoretical assumption that an antiferromagnetic interface coupling is necessary to observe positive exchange bias. (c) 2000 The American Physical Society.

OSTI ID:
20215092
Journal Information:
Physical Review. B, Condensed Matter and Materials Physics, Vol. 61, Issue 2; Other Information: PBD: 1 Jan 2000; ISSN 1098-0121
Country of Publication:
United States
Language:
English