The Morphology and Magnetic Properties of FePt Antidot Arrays on Porous Anodic Alumina Templates

Large-area magnetic antidot arrays are prepared by depositing FePt on porous anodic alumina (PAA) templates. The pore density (ρ), diameter (D), and interpore distance (D)of the fabricated antidot arrays all can be tuned by the PAA templates. The nanopores can serve as domain-wall pinning sites, which affect magnetic properties of the samples. The magnetic properties of antidot arrays depend sensitively on the antidot morphology, such as D, d, and film thickness. Both perpendicular and parallel coercivity (H_c) increase monotonically with increasing the density of pores. Keeping the ρ constant, both (H_c) first increase with (D), until a maximum is reached at a critical D. Further increasing pore diameter leads to a decrease in (H_c). The pinning effect on FePt with different thicknesses is also investigated.