Energetics, synthesis, and structural characteristics of ferromagnetic metals for shape memory alloy and catalysis

Abstract

The ferromagnetic metals iron and nickel have valence d electrons that allow for magnetic responsivity and catalytic activity, enabling their use in a variety of applications. The iron–palladium alloy Fe70Pd30 is a ferromagnetic shape memory alloy whose magnetostriction and pseudoelasticity can be exploited for potential use as a controllable nanoactuator. Here we synthesize and characterize Fe70Pd30 nanomaterials, a better understanding of whose properties at the nanoscale may lead to its practical deployment. We developed a pulsed electrodeposition and thermal annealing process to produce high aspect ratio nanowires in an alumina template and investigate the size effects on temperature-induced austenite–martensite phase transition with the crystal structure. We also explore the energetics of nickel surfaces to improve catalyst design for efficiency in industrial reactions. Here we measure the adsorption energies of formic acid and formate intermediates on nickel and nickel oxide (111) surfaces to provide benchmarks for more accurate calculations. This is performed by single-crystal adsorption calorimetry to directly measure heats of adsorbate formation.