High coercivity of ultra-high-density ordered Co nanorod arrays

We report on magnetic properties of well-ordered ultra-high density (1.25x1 0(12)/in(2)) arrays of vertically oriented high-aspect-ratio Co nanorods ha ving a 14nm diameter. The arrays were fabricated by electrodeposition withi n the pores of a nanoscale template derived from films of diblock copolymer s. We find large coercivity enhancement (H(c)approximate to3 kOe at 5 K and 800 Oe at 300 K) relative to a continuous Co film of comparable thickness. The high coercivity in our ordered arrays is contrasted with a distinct de crease of coercivity below similar to 50 nm rod diameter in a randomly posi tioned nanorod assembly. (C) 2001 Elsevier Science B.V. All rights reserved .