Tunable magnetocrystalline easy axis in cobalt nanowire arrays by zinc additive

Abstract

tA new approach to tuning the crystalline characteristics and magnetic properties of cobalt nanowire(NW) arrays embedded in AAO templates is reported using zinc additive. This is realized by adding lowconcentrations of Zn when pulse-electrodepositing cobalt NWs while also increasing the solution pHfrom 3 to 5. Using hysteresis loop measurements with a magnetic field applied parallel to the NW axis,coercivity and squareness of pure cobalt NWs increased from 890 Oe and 0.45 to 2150 Oe and 0.93 inCo97Zn3NWs, respectively, using a Zn concentration of 0.01 M at pH = 4. XRD patterns obtained from thecobalt-rich CoZn NWs revealed that the crystalline texture of cobalt changes from [1 0 0] direction to[1 0 1] and [0 0 2] at pH = 3 and 4, respectively. For the latter, the magnetocrystalline easy axis of cobaltrotates from nearly perpendicular to parallel to the NW axis, induced by the incorporation of zinc intothe hcp structure of cobalt.