CHARACTERIZATION OF MAGNETIC NANOPARTICLES AND FERROFLUIDS BY MÖSSBAUER SPECTROSCOPY

G. A. PASQUEVICH; ARRIETA GAMARRA, D.; MELE, NICOLÁS G.; MENDOZA ZÉLIS P; FRANCISCO H SANCHEZ

Vitoria

Conferencia; XVII Latin American Conference On The Applications Of The Mössbauer Effect; 2022

Universidade Federal do Espírito Santo

Mössbauer effect spectroscopy has great potential for characterizing magnetic nanoparticles (NPs) of Fe oxides. In particular, the particle size distribution and composition phases are characteristics of the system that modify the spectral pattern in ways that are distinguishable. The characterization is limited to powder samples or frozen solutions because of the sensitivity of the technique to the relative velocity between the emitting and receiving nuclei. The movement of the NPs eventually leads to spectral dispersion; therefore, the magnitude of this mobility can be quantified by determining the generated spectral dispersion. In this work, we present different approaches to analyze magnetic nanoparticle systems by Mössbauer effect spectroscopy. In particular we will discuss the inference of the size distribution in room temperature Mössbauer effect spectra based on the dependence of the effective hyperfine field on the size of the magnetic nanoparticles, with special spectral patterns proposed for the sub-spectra of the nanoparticles, depending on the phase they constitute. The present nanoparticles and colloids under study correspond to nanoparticles of phases between maghemite and magnetite with diameters between 10 and 20 nm, coated with citric acid to give them stability in aqueous solutions.