PNNL

Abstract

The magnetostrictive nanobar and its array were recently induced as a high performance biosensor platform. In this paper, we report the fabrication and the characterization of magnetostrictive nanobars based on Fe-B alloy. The nanobars were synthesized using a template-based electrochemical deposition method. The composition and microstructure of the Fe-B nanobars are directly related to their performance as the biosensor platform. The Fe-B nanobar arrays and individual nanobar were characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM), as well as Auger electron spectroscopy (AES). Morphologically, nanobars are featured by very flat top and smooth cylindrical surface, which are critical factors for obtaining high performance as sensor platform. Structurally, electron diffraction reveals that the Fe-B nanobar is amorphous. AES analysis indicates that the nanobar shows no significant compositional variation along the length direction. It is found that the nanobars were covered by an oxidization layer of a typical thickness of ~ 10 nm. It is believed that this oxidation layer is related to the passivation of nanobars in air. High temperature annealing and subsequent structural analysis indicate that the Fe-B nanobars possess a good thermal stability.