No abstract

The study of Giant Magnetoimpedance (GMI) effect of the amorphous alloys system of Fe 72-x Co x Nb 6 B 10 Si 11 Cu 1 (for x = 35 and x = 40 at. percent Co) and AC magnetic susceptibility for the amorphous alloy of Fe 37 Co 35 Nb 6 B 11 Si 10 Cu 1 composition are presented in this chapter. The importance of GMI effect for the improvement of technological applications in sensor devices in amorphous magnetic Fe-and Co-based alloys is introduced; then it is described as the experimental procedure of magnetoimpedance and AC magnetic susceptibility measurements. The obtained results are discussed and finally the conclusions are presented.

This research work used Musa Paradisiaca (banana) peels as a natural solvent, assorted with the precursor AgNO3 (10 mM) to perform the green synthesis of silver nanoparticles. The phytochemical components present in the Musa Paradisiaca peel extracts were determined by gas chromatography coupled to a mass spectrometer (GC-MS), and it was possible to identify the compounds: 1.2 Ethanediol (60.0261 %) and 2.3 Butanediol (11.2 %); these -diols represent a highly reducing agent for metals, since they act as a solvent for the metal precursor behaving as a reducing agent, and facilitating the formation of nanoparticles. Likewise, the synthesized silver nanoparticles were subjected to a washing and drying treatment to be subsequently characterized by means of UV-Vis and XRD techniques, resulting in a wavelength of 411 nm, which is characteristic of these metallic nanoparticles, and achieving the identification of the face-centered cubic structure (fcc) of the metallic silver, with an average particle size of 21.8 nm according to the Debye-Scherrer equation.

Las aleaciones magnéticas nanoestructuradas a base de FeCo se destacan entre las aleaciones magnéticas convencionales a base de Fe por presentar óptimas propiedades magnéticas blandas, requeridas en una variedad de aplicaciones tecnológicas, industriales y biomédicas. En este trabajo se presentan los resultados obtenidos de la caracterización térmica por calorimetría diferencial de barrido y termogravimetría magnética de polvos puros de Fe y Co, y de polvos magnéticos nanoestructurados a base de Fe50Co50 y Fe65Co35 preparados por el método de Aleado Mecánico de elevada energía. Por medio de estas técnicas y bajo la influencia de diferentes atmósferas inertes como Helio (He), Nitrógeno (N2) y Argón (Ar), se evidenciaron los eventos térmicos que tienen lugar desde temperatura ambiente hasta 900 °C para muestras molidas a diferentes tiempos (0, 10, 15, 20 y 25 horas), eventos tales como las temperaturas de transición magnética y de orden – desorden características de este tipo de muestras y del proceso de molienda. Palabras clave: Caracterización Térmica, Análisis Termogravimétrico, Termogravimetría Magnética, Aleaciones Nanoestructuradas, Aleado Mecánico, Transiciones de Fase.

No abstract