Magnetic and Structural Properties of Electrochemically Self-Assembled Fe _1-xCo _x Nanowires

Fe _1-xCo _x (0 ≤ x ≤ 1) nanowires have been self-assembled by electrodeposition in porous alumina films. The crystal structure is bee at the Fe end. With increased addition of Co, the crystal structure remains bcc until about 67% addition of Co. At the Co end, the structure is a mixture of hcp and fcc. Magnetic studies show very high coercivities for the Fe-Co alloys in the bcc phase. For Fe _0.67Co _0.33 nanowires of diameter 9 nm, the coercivity is about 2900 Oe, whereas for Fe _0.33Co _0.67 nanowires, it is about 2850 Oe. Temperature and size dependence of magnetic properties show no indication of superparamagnetic effects down to wire diameters of 9 nm.