TUNABLE PERPENDICULAR EXCHANG BIAS AND COERCIVITY IN [Co/Pd]/IrMn MULTILAYERS

Abstract

The effect of exchange bias (EB) has been investigated in ferromagnet/antiferromagnet (FM/AFM) bilayers for more than fifty years. Up to now, most studies have focused on conventional in-plane magnetic anisotropy materials. In this study, the FM/AFM systems with perpendicular magnetic anisotropy were fabricated using a magnetron sputtering system. Structural and magnetic properties of the fabricated multilayers (MLs) were carried out by using X-Ray Diffraction (XRD) and Vibrating Sample Magnetometer (VSM) systems, respectively. The dependence of the exchange bias field and coercivity of [Co/Pd]/IrMn MLs on the multilayer repetition number, thickness of Co layer and Pd layer have been investigated systematically. The experimental results showed that the developed MLs have a strong perpendicular magnetic anisotropy and a large perpendicular exchange bias at room temperature. Interestingly, the perpendicular exchange bias field (H_EB) and coercivity (H_C) of [Co/Pd]/IrMn MLs can be easily tuned by tuning i) multilayer repetition number N, ii) Co thickness (t_Co); and iii) Pd thickness (t_Pd).