  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.
