Tunable magnetocrystalline easy axis in cobalt nanowire arrays by zinc additive

• Pure Co and Co-rich CoZn NW arrays were fabricated into AAO templates.
• Effect of Zn additive on magnetic properties and crystal structure was investigated.
• Coercivity and squareness of Co NWs increased up to 2150 Oe and 0.93 by Zn additive.
• Incorporation of Zn rotated Co c-axis from perpendicular to parallel to NW axis.

A 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 low concentrations of Zn when pulse-electrodepositing cobalt NWs while also increasing the solution pH from 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 in Co97Zn3 NWs, respectively, using a Zn concentration of 0.01 M at pH = 4. XRD patterns obtained from the cobalt-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 cobalt rotates from nearly perpendicular to parallel to the NW axis, induced by the incorporation of zinc into the hcp structure of cobalt.

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