Multiferroically composed exchange bias systems

Magnetoelectric (ME) antiferromagnetic Cr2O3, being exchange coupled to a ferromagnetic multilayer (Pt/Co/Pt)(n), n >= 1, is treated as a multiphase multiferroic material with sophisticated multifunctional properties. It is shown that the exchange bias (EB) of the ferromagnetic hysteresis loop cannot only be controlled by the magnetic freezing field, H-fr, but additionally also by an external electric freezing field, E-fr, via the ME effect of Cr2O3. Either a gradual shift or complete switching from -H-EB to +H-EB on the magnetic field axis are possible. Here the influence of E-fr at constant H-fr on both the coercive field, H-c, and the anti ferromagnetic domain wall susceptibility, Delta chi, and on the temperature dependence of the ME controlled quantities H-c(T) and H-EB(T) is reported.