Exchange anisotropy in epitaxial and polycrystalline NiO/NiFe bilayers

Journal Article · Thu Oct 01 04:00:00 EDT 1998 · Physical Review, B: Condensed Matter

DOI:https://doi.org/10.1103/PhysRevB.58.8566· OSTI ID:659326

Michel, R P; Chaiken, A ^[1]; Wang, C T ^[2]; Johnson, L E ^[1]

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1. Materials Science and Technology Division, Lawrence Livermore National Laboratory, Livermore, California 94551 (United States)
2. Department of Materials Science and Engineering, Stanford University, Palo Alto, California 94305 (United States)

(001)-oriented NiO/NiFe bilayers were grown on single crystal MgO (001) substrates by ion beam sputtering in order to determine the effect that the crystalline orientation of the NiO antiferromagnetic layer has on the magnetization curve of the NiFe ferromagnetic layer. The simplest model predicts no exchange anisotropy for the (001)-oriented NiO surface, which in its bulk termination is magnetically compensated. Nonetheless exchange anisotropy is present in the epitaxial films, although it is approximately half as large as in polycrystalline films that were grown simultaneously. The surface anisotropy in the epitaxial films is found to contain cubic and unidirectional components, while that in the polycrystalline film is best described by a uniaxial plus unidirectional anisotropy. Experiments indicate that differences in exchange field and coercivity between polycrystalline and epitaxial NiFe/NiO bilayers couples arise due to variations in induced surface anisotropy. Implications of these observations for models of induced exchange anisotropy in NiO/NiFe bilayer couples will be discussed. {copyright} {ital 1998} {ital The American Physical Society}

• OSTI ID: 659326
• Journal Information: Physical Review, B: Condensed Matter, Journal Name: Physical Review, B: Condensed Matter Journal Issue: 13 Vol. 58; ISSN PRBMDO; ISSN 0163-1829
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ANISOTROPY
ANTIFERROMAGNETIC MATERIALS
COERCIVE FORCE
EXCHANGE INTERACTIONS
FERROMAGNETISM
IRON ALLOYS
LAYERS
MAGNETIC PROPERTIES
NICKEL ALLOYS
NICKEL COMPOUNDS
NICKEL OXIDES
ORIENTATION
SPIN ORIENTATION
THIN FILMS