Cobalt oxide/ferromagnet bilayers: Exchange coupling and dominance of the antiferromagnet
Hahn-Meitner-Institut Berlin - Glienicker Strasse 100,
D-14109 Berlin, Germany
Accepted: 9 October 2003
Using cobalt oxide/ferromagnet bilayers with strong magnetic coupling, the nature of the interfacial exchange interaction in exchange bias systems has been investigated. For , and as ferromagnetic materials, an almost linear temperature dependence of the exchange bias field and a common blocking temperature of 175 have been found. Additionally, an inverse proportionality between and the thickness of the ferromagnetic layer has been confirmed. The average coupling energies at T=10 have been determined to 0.90, 1.02 and 0.80 for , and bilayers, respectively. The presently observed behavior strongly deviates from recent theoretical mean-field analysis and other experimental investigations on antiferromagnetic/ferromagnetic bilayers.
PACS: 75.70.Cn – Magnetic properties of interfaces (multilayers, superlattices, heterostructures) / 75.30.Et – Exchange and superexchange interactions / 75.30.Gw – Magnetic anisotropy
© EDP Sciences, 2003