  When a ferromagnet is in proximity with an antiferromagnet, lateral length
scales such as the respective magnetic domain sizes drastically affect the
exchange bias. Bilayers of FeF2 and either Ni, Co or Fe are studied using SQUID
and spatially resolved MOKE. When the antiferromagnetic domains are larger than
or comparable to the ferromagnetic domains, a local, non-averaging exchange
bias is observed. This gives rise to unusual and tunable magnetic hysteresis
curves.
