ENHANCEMENT OF PERPENDICULAR EXCHANGE BIAS IN [Co/Pd]/IrMn SYSTEM BY ULTRATHIN CoFe INSERTION LAYER

Abstract

In this study, we investiged the effect of an ultrathin CoFe insertion layer on perpendicular exchange bias in the [Co/Pd]/IrMn systems. These multilayers were deposited by magnetron sputtering. The structural and magnetic properties of the deposited multilayers were examined by X-ray diffractometer and Vibration sample magnetometer. The experimental results showed that the value of the perpendicular exchange bias field (H_EB) of [Co/Pd]/IrMn multilayers at room temperature is relatively high (H_EB ~ 98 Oe). However, H_EB is significantly enhanced when an ultrathin layer of CoFe (t_CoFe = 0.3 – 1.2 nm) is inserted between the [Co/Pd] ferromagnetic multilayers and the IrMn antiferromagnetic layer. The highest value of H_EB is 205 Oe with t_CoFe = 0.8 nm which is more than twice higher than that of the system without CoFe insertion layer.