Magnetization reversal, asymmetry, and role of uncompensated spins in perpendicular exchange coupled systems

Soft x-ray resonant magnetic scattering has been used to investigate the element-selective microscopic magnetization reversal behavior of room temperature perpendicular exchange coupled ferromagnetic∕antiferromagnetic (F∕AF) systems and to study the role of the interfacial coupling strength on it. Different nucleation processes and domain size distributions along the decreasing and increasing branches of the reversal have been found. The size of the magnetic domains during reversal depends on both the F anisotropy and F∕AF coupling strength, decreasing when one of them increases. Evidence of the exchange bias (coercivity enhancement) being induced by pinned (unpinned) uncompensated AF interfacial spins is also shown.