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

Ferromagnetic Co nanowires have been electrodeposited into self-assembled p orous anodic alumina arrays. Due to their cylindrical shape, the nanowires exhibit perpendicular anisotropy. The coercivity, remanence ratio, and acti vation volumes of Co nanowires depend strongly on the length, diameter, and spacing of the nanowires. Both coercivity and thermal activation volume in crease with increasing wire length, while for constant center-to-center spa cing, coercivity decreases and thermal activation volume increases with inc reasing wire diameter. The behavior of the nanowires is explained qualitati vely in terms of localized magnetization reversal. (C) 2000 American Instit ute of Physics. [S0021-8979(00)35208-2].