Magnetic properties of self-assembled Co nanowires of varying length and diameter

TLDR

Ferromagnetic Co nanowires electrodeposited into self‑assembled porous anodic alumina arrays exhibit perpendicular anisotropy due to their cylindrical shape. Coercivity, remanence ratio, and activation volumes of Co nanowires depend strongly on length, diameter, and spacing, with both coercivity and thermal activation volume increasing with wire length, while for constant center‑to‑center spacing coercivity decreases and activation volume increases with increasing diameter.

Abstract

Ferromagnetic Co nanowires have been electrodeposited into self-assembled porous anodic alumina arrays. Due to their cylindrical shape, the nanowires exhibit perpendicular anisotropy. The coercivity, remanence ratio, and activation volumes of Co nanowires depend strongly on the length, diameter, and spacing of the nanowires. Both coercivity and thermal activation volume increase with increasing wire length, while for constant center-to-center spacing, coercivity decreases and thermal activation volume increases with increasing wire diameter. The behavior of the nanowires is explained qualitatively in terms of localized magnetization reversal.