  Magnetization and magnetic microstructure of top soft magnetic layer (Fe),
which is exchange spring coupled to bottom hard magnetic layer ($L1_0$ FePt) is
studied using high resolution Kerr microscopy. When the sample (FePt/Fe) is at
remanent condition of hard magnetic layer, considerable shifting of Fe layer
hysteresis loop from centre i.e., exchange bias phenomena is observed. It is
observed that one can tune the magnitude of exchange bias shift by reaching the
remanent state from different saturating fields ($H_{SAT}$) and also by varying
the angle between measuring field and $H_{SAT}$. The M-H loops and domain
images of top soft Fe layer demonstrates unambiguously that soft magnetic layer
at remanent state in such exchange coupled system is having unidirectional
anisotropy. An analogy is drawn and the observations are explained in terms of
the mostly accepted models of exchange bias phenomena exhibited by bilayers
consisting of ferromagnetic(FM) and anti-ferromagnetic (AFM) layers, when the
AFM layer is field cooled across $N\acute{e}el$ transition temperature.
