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Structural and magnetic studies of monophasic maghemite (γ-Fe2O3) magnetic nanocrystallites (MNCs) synthesized by the co-precipitation chemical route are reported in this paper. For the synthesis, a starting precursor of magnetite (Fe3O4) in basic medium was oxidized at room temperature by adjusting the pH = 3.5 at 80°C in an acidic medium without surfactants. X-ray diffraction (XRD) pattern shows widened peaks indicating nanometric size and Rietveld Refinement confirms only one single-phase assigned to γ-Fe2O3 MNCs. High Resolution Transmission Electron Microscopy (HR-TEM) demonstrates the formation of nanoparticles with diameter around D ≈ 6.8 ± 0.1 nm which is in good agreement with Rietveld Refinement (6.4 ± 1 nm). A selected area electron diffraction pattern was carried out to complement the study of the crystalline structure of the γ-Fe2O3 MNCs. M(H) measurements taken at different temperatures show almost zero coercivity and remanence indicating superparamagnetic domain and high magnetic saturation.

The Rietveld refinement method has taken high relevance since its creation. Nowadays, it is an useful tool in many fields of industry, materials science, and technology. For these reasons, it becomes a need for scientists and engineers whom pretend to use it for proper analysis of their materials. However, the initiation in the method can be slow, taking into account the accelerated rhythm of the research and economic demands. Thus, this work is an intend to fulfill this hole, providing the basic foundations and methodology of the Rietveld refinement in a brief way, this along with the results of its application in superconducting samples of Yttrium Barium Copper Oxide and magnesium diboride, and functional magnetic nanoadsorbents of maghemite and a multiphasic composite (iron oxide, hydroxyapatite and secondary phases). In the process, an in-detail protocol was designed and provided. It was concluded that the samples were successfully refined and that this work represents a fast introduction to the Rietveld method for which beginners can obtain good results while making correct interpretations ofthe whole refinement process., El método de refinamiento Rietveld ha adquirido gran relevancia desde su creación. Hoy en día, es una herramienta útil en muchos campos de la industria, ciencia de materiales y tecnología. Por estas razones, se convierte en una necesidad para científicos e ingenieros que pretenden utilizarlo para un análisis adecuado de sus materiales. Sin embargo, la iniciación en el método puede ser lenta, teniendo en cuenta el ritmo acelerado de la investigación y las demandas económicas. Así, este trabajo es un intento de cubrir este agujero, proporcionando los fundamentos básicos y la metodología del refinamiento de Rietveld de manera breve, esto junto con los resultados de su aplicación en muestras superconductoras de Óxido de Itrio Bario Cobre y diboruro de magnesio, y nanoadsorbentes funcionales magnéticos de maghemita y un compuesto multifásico (óxido de hierro, hidroxiapatita y fases secundarias). En el proceso, se diseñó y proporcionó un protocolo detallado. Se concluyó que las muestras fueron refinadas con éxito y que este trabajo representa una rápida introducción al método de Rietveld por el cual usuarios principiantes pueden obtener buenos resultados mientras hacen interpretaciones correctas de todo el proceso de refinamiento.