Synthesis and Characterization of Fe70Pd30 Nanohelices

Abstract

A device performing controlled actuation and motion at the nanoscale will be the essential component for future nanoelectromechanical systems. Fe70Pd30 ferromagnetic shape memory (FSMA) alloy shows multi-functional effects, including conventional shape memory effect, superelasticity, ferromagnetic shape memory effect, magnetostriction, and Invar effect. These unique properties make Fe70Pd30 alloy a promising nanoactuation material. This work aims to fabricate Fe70Pd30 nanosprings which serve as the key building block of linear spring actuator in nanoscale. I develop a synthesis route of potentiostatic-galvanostatic mix pulse electrodeposition using a porous anodic alumina (PAA)-mesoporous silica hybrid template for fabrication of Fe70Pd30 nanosprings with precise chemical composition. This synthesis route can be applied as a general method for nanosprings synthesis and not limited to specific target materials. Then I explore the crystal structure and temperature induced martensite phase transformation of annealed Fe70Pd30 nanosprings which are essential for their potential use as shape memory smart materials. Finally, I investigate the various microphases of Fe-Pd nanowires that originate from the block copolymer-silica co-self-assembly under cylindrical confinement via experiment and simulation.