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In the last decade, magnetic nanomaterials have been widely used in the fields of chemistry, physics, engineering, and medicine due to their optical, magnetic, and conductive properties, and as contrast agents in magnetic resonance. Their influence in the treatment of cancerous tumors has been evaluated and has sparked great interest in its use in environmental repair systems such as magnetic absorbers that trap metal particles and some contaminants. Here we analyze the influence of process parameters to obtain magnetic nanoparticles under three chemical synthesis methods. Its morphological characterization was performed by scanning electron microscopy (SEM), its elemental composition by energy dispersive spectroscopy (EDS), and its structure by x-ray diffraction (XRD). Our results showed that the obtention method had a great influence as evidenced by the variability in nanoparticle sizes. It is worth highlighting that we obtained particles at a nanometric scale, especially Fe3O4 (magnetite) and Fe2O3 (maghemite) structures, with potential superparamagnetism properties that could open a wide range of future applications for the production of these materials at low cost and easy access.

Perovskite-like materials which include magnetic elements have relevance due to the technological perspectives in the spintronics industry. In this work, the magnetic, structural and electronic properties of the Ba2CoMoO6double perovskite are investigated. Calculations are carried out through the Full-Potential Linear Augmented Plane Wave method within the framework of the Density Functional Theory with exchange and correlation effects in the Generalized Gradient and Local Density approximations, including spin polarization. From the minimization of energy as a function of volume using the Murnaghan’s state equation the equilibrium lattice parameter and cohesive properties of this compound were obtained. The study of the electronic structure was based in the analysis of the electronic density of states, and the band structure, showing that this compoundevidences a conductive character for a spin channel and insulation for the other, and presents an integer value for the effective magnetic moment (3.0 μB), which allows it to be classified as a half-metallic material. The effects of pressure and temperature on thermophysical properties such as specific heat, Debye temperature, coefficient of thermal expansion and the Grüneisen parameter were calculated and analyzed from the state equation of the system. The obtained results reveal that, in the low temperature regime, the specific heat at constant volume and pressure presents an analogous behavior to each other, with a tendency to the limit of Dulong-Petit typical of the structures of cubic perovskite type, showing a value of 246.3 J/mol.Kat constant volumeand slightly higher values at constant pressure. The dependence of the coefficient of thermal expansion, the temperature of Debye and the Grüneisen parameter with the increase in temperature is discussed in relation to other perovskite-like materials.

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