Co–Fe–Al Heusler Alloy Nanowires Prepared by Electrospinning Route for Spintronics Applications

Co–Fe–Al nanowires were synthesized by an electrospinning method. The near-stoichiometric composition of Co49Fe25Al26 contains ∼2% Fe0.1Co0.9 phase along with the ternary Heusler alloy phase exhibiting a B2-type atomic order. In contrast, off-stoichiometric Co45Fe29Al26 nanowires were obtained in an impurity-free, single-phase form with a B2 structure. Both nanowires were polycrystalline with smooth and continuous morphology. These nanowires demonstrate moderate saturation magnetization (0.81 μB/f.u. at 5 K), high effective anisotropy constant (1.45 × 106 erg/cm3 at 5 K), and high Curie temperature (811 K) values. The Heusler alloy phase was stable until 811 K above which it decomposed into binary Al3Co phase and Fe phase. This study provides several information on the microstructure-, composition-, and temperature-dependent magnetic properties and phase stability of Co–Fe–Al nanowires. These studies also reveal the potential of these Heusler alloy nanowires in fabricating efficient spintronic device and magnetic data storage applications.