Approach to fabricating Co nanowire arrays with perpendicular anisotropy: Application of a magnetic field during deposition

Cobalt (Co) nanowire arrays were electrodeposited into the pores of polycar bonate membranes. A magnetic field parallel or perpendicular to the membran e plane was applied during deposition to control the wire growth. X-ray dif fraction, transmission electron microscopy, and vibrating sample magnetomet er were employed to investigate the structure as well as the magnetic prope rties of the nanowire arrays. The results show that the magnetic field appl ied during deposition strongly influences the growth of Co nanowires, induc ing variations in their crystalline structure and magnetic properties. The sample deposited with the field perpendicular to the membrane plane exhibit s a perpendicular magnetic anisotropy with greatly enhanced coercivity and squareness as a result of the preferred growth of Co grains with the c axis perpendicular to the film plane. In contrast, the deposition in a parallel magnetic field forces Co grains to grow with the c axis parallel to the fi lm plane, resulting in in-plane anisotropy. (C) 2001 American Institute of Physics.