  We investigated the perpendicular exchange bias (PEB) switching from
negative- to positive-exchange bias state for Cr2O3/Pt/Co exchange coupling
thin film system exhibiting positive exchange bias phenomena. By changing Pt
spacer layer thickness or measurements temperature, we demonstrated the control
of two kind of intermediate state of the switching; the double hysteresis loop
indicating local, non-averaged PEB, and single hysteresis loop indicating
averaged PEB. We proposed the way to control the lateral ferromagnetic domain
though the control of PEB magnitude.
