Controlling the oxidation of magnetic and electrically conductive solid-solution iron-rhodium nanoparticles synthesized by Laser Ablation in Liquids

TL;DR

This paper investigates the synthesis of FeRh nanoparticles via pulsed laser ablation in liquids and explores methods to control their oxidation, analyzing the effects of various environmental factors and optimizing conditions for reduced oxidation.

Contribution

It introduces a controlled synthesis process for FeRh nanoparticles with minimized oxidation, using laser ablation in liquids and comprehensive analysis of oxidation sources.

Findings

Oxidation sources identified as dissolved oxygen, bound oxygen, and atmospheric oxygen.

Optimized ablation conditions significantly reduce oxidation levels.

Magnetophoretic separation effectively isolates B2-FeRh nanoparticles.

Abstract

This study focuses on the synthesis of FeRh nanoparticles via pulsed laser ablation in liquid and on controlling the oxidation of the synthesized nanoparticles. Formation of monomodal {\gamma}-FeRh nanoparticles was confirmed by transmission electron microscopy (TEM) and their composition confirmed by atom probe tomography (APT). On these particles, three major contributors to oxidation were analysed: 1) dissolved oxygen in the organic solvents, 2) the bound oxygen in the solvent and 3) oxygen in the atmosphere above the solvent. The decrease of oxidation for optimized ablation conditions was confirmed through energy-dispersive X-ray (EDX) and M\"ossbauer spectroscopy. Furthermore, the time dependence of oxidation was monitored for dried FeRh nanoparticles powders using ferromagnetic resonance spectroscopy (FMR). By magnetophoretic separation, B2-FeRh nanoparticles could be extracted from the solution and characteristic differences of nanostrand formation between {\gamma}-FeRh and B2-FeRh nanoparticles were observed.