Exchange biasing and coercivity enhancement in CoCr/FeMn bilayers with granular ferromagnet

Exchange biasing is studied in Co80Cr20 (CoCr)/FeMn bilayers with a ferromagnetic material granular CoCr. Unique exchange biasing characteristics closely related to the microstructures and magnetization reversal process of granular CoCr have been observed. Although the exchange field in CoCr/FeMn bilayers is inversely proportional to the CoCr layer thickness, similar to the conventional ferromagnet/antiferromagnet bilayers, the coercivity HC is found to increase with increasing CoCr layer thickness. More importantly, HC of the CoCr/FeMn bilayers is smaller than that of CoCr single layer films.