Exchange bias and ferromagnetic coercivity in heterostructures with antiferromagnetic Cr2O3

The perpendicular exchange bias effect in multilayer systems Cr2O3(0001)/[Co/Pt](n), n >= 1, is strongly correlated with the temperature dependence of the antiferromagnetic order parameter in Cr2O3 in the vicinity of its Neel temperature. A crossover between surface and 3D bulk critical behavior is found for the interface moments of Cr2O3. In addition, for the first time, a specific exchange bias-related contribution to the ferromagnetic coercive field could be separated. (C) 2011 American Institute of Physics. [doi:10.1063/1.3621460]