Electrochemical deposition of Fe 1 − x Ga x nanowire arrays

Nanowires of the Fe-Ga alloy system, Fe 1 − x Ga x ( 0.1 ⩽ x ⩽ 0.25 at. % ) , were fabricated using electrochemical deposition into nanoporous anodic alumina. Fe-Ga alloys are magnetically soft, mechanically robust, ductile, and have large magnetostriction. High aspect ratio nanowires with varying diameters and lengths were fabricated in arrays and were collectively and individually characterized using scanning electron microscopy and energy dispersive spectroscopy. The magnetic response of the array was also measured using vibrating-sample magnetometry. The Ga composition was controlled by optimizing deposition parameters such as ion concentration, buffer acids, agitation, and applied voltage. Through the analysis of pure Fe and pure Ga depositions, it was predicted that the Ga 3 + ions would be depleted more quickly from the electrolyte than the Fe 2 + ions. This hypothesis was supported by compositional analysis along alloy wires showing that the Ga composition decreased along the length of the wires.