MODULATION OF PERPENDICULAR MAGNETIC ANISOTROPY AND EXCHANGE BIAS IN [Co/Pd]-IrMn MULTILAYER NANO-ANTIDOT ARRAYS

Abstract

The manipulation of magnetic anisotropy and exchange bias field (H_EB) in ferromagnet/antiferromagnet (FM/AFM) thin films could be the key in the development of the next generation of spintronic devices. In this paper, the possible modulation of the magnetic anisotropy and H_EB was investigated by the structural parameters of the nanoporous FM/AFM multilayer films. The [Co/Pd]-IrMn multilayers were sputtered on flat SiO₂ and self-organized nanoporous oxide (Al₂O₃, TiO₂) substrates with different pore size and surface morphology. The influence of surface morphology and pore size on the structure and magnetic of the nanoporous [Co/Pd] and [Co/Pd]-IrMn films were investigated carefully. All films (flat and porous ones) exhibit strong perpendicular magnetic anisotropy and large H_EB at room temperature, specially in the nanoporous TiO₂-[Co/Pd]-IrMnfilm. Moreover, a significant increase of the coercivity as well as a reduction of the remanence of the developed nanoporous thin films, which depends on the pore size and surface morphology, was also observed.