Gruppo di Fisica Statistica

Positive exchange bias is shown to occur in (ferromagnetic (FeSn)/ferrimagnetic (FeGd)) bilayers. As the net magnetisation in the ferrimagnetic layer is not zero, in contrast to "regular" exchange bias observed in ferro/antiferromagnetic systems, we could detect the magnetic configuration of both layers by magnetisation, ac-susceptibility and resistivity measurements. The results allow us to conclude that the exchange bias effect is due to an antiferromagnetic coupling at the interface between the magnetisation of the layers through a domain wall located at the interface. The influence of this magnetic domain wall on transport and ac-susceptibility is presented.