Synthesis and Characterization of Ni–Fe–B Nanotubes

We have prepared Ni-Fe-B nanotube arrays of length 20 μm and outer diameter 400 nm in polycarbonate membranes via electroless deposition using dimethylamine borane as a reducing agent. The alloy composition was varied by controlling the FeSO₄ concentration in the deposition solution, and the effect of this variation on the nanostructures and magnetic properties was investigated. We found that the specific magnetization of the nanostructures varies linearly with Fe content, with a maximum value of 84.5 JT^-1 kg^-1 obtained for Ni₆₂Fe₃₈-B. The Ni-Fe-B nanotubes are magnetically soft with an increase in Fe content, resulting in a reduced coercivity and squareness. Our results also show that vortex mode is the dominant reversal magnetization mechanism in the nanotubes. In this paper, we show that the magnetic properties of Ni-Fe-B nanotubes can be tailored through varying the Fe content.