Accession Number:

ADP012264

Title:

Oscillatory Angular Dependence of Exchange Bias for Epitaxial NiO-Co (001) Bilayers

Descriptive Note:

Conference proceedings

Corporate Author:

CENTRE NATIONAL DE LA RECHERCHE SCIENTIFIQUE TOULOUSE (FRANCE)

Report Date:

2001-04-01

Pagination or Media Count:

6.0

Abstract:

We have sputter-deposited NiO-Co bilayers on MgO 001 substrates. NiO grows epitaxially on MgO at 900 deg C and subsequently the room deposited 80 A thick Co films have a fcc crystal structure in epitaxy with the oxide underlayer. These samples were warmed up to 300 deg C and then zero-field or field cooled through the NiO Neel temperature a 300 Oe magnetic field was applied along the 100 or the 110 MgO axis. Magnetic hysteresis loops were obtained by magneto-optical Kerr effect, the magnetic field being oriented in the plane of the substrate for various angles alpha with respect to the 100 direction. The usually expected behavior for such experiments is a smooth angular a dependence of the exchange bias Hsub E close to a cosine with only one sign change over 180 deg. The high crystallographic coherence of our NiOCo bilayers induces a very unusual oscillatory HE alpha dependence with several sign changes according to the NiO axis field application. Despite of the Co magnetization switching mechanism which is not a pure coherent rotation. we propose a Stoner-Wohlfhart model including four fold anisotropy and unidirectional exchange anisotropy giving a realistic description of these typical magnetic properties.

Subject Categories:

  • Crystallography
  • Electricity and Magnetism
  • Properties of Metals and Alloys

Distribution Statement:

APPROVED FOR PUBLIC RELEASE