(1) LNMH-CNRS, ONERA, 2 avenue Edouard Belin, 31400 Toulouse, France;(2) CEMES CNRS, 29 rue Jeanne Marvig, 31055 Toulouse, France
Abstract:
We have sputter-deposited NiO-Co bilayers on MgO(001) substrates.
NiO and Co grow epitaxially on MgO and reproduce its fcc
structure. The high quality of our samples, in terms of flatness and crystallographic coherence of
the interface, allows the observation of an additional fourfold magnetic anisotropy
term by standard magnetometry. This term is induced by interfacial interaction assigned to
the same origin as exchange bias. Additional measurements of
exchange bias azimuthal dependence versus the crystallographic
axes of the film plane reveal unusual behaviors with several sign
changes related to this fourfold anisotropy.