Colloidal synthesis of iron titanate-based nanocomposites exploiting the interaction of solutions of binary oxide nanoparticles, Fe2O3 and TiO2, was investigated with respect to the pH of the reaction medium and the conditions used for the synthesis of the reactants. It has been demonstrated that while the phase composition of the products is rather analogous, involving the formation of iron titanate phases on the grain boundaries of the binary oxide particles, the morphology of the resulting aggregates can be a matter of pH control. The self-assembly mechanisms are guided by the surface charge of the particles, offering nanorod regular colloid crystal structures of altering particles with opposite initial charges at neutral pH and globular aggregates with random distribution of uniformly charged particles at low pH as revealed by DLS and high-resolution TEM studies. The produced materials demonstrated enhanced photocatalytic activity compared to the iron titanates produced by conventional techniques. Magnetic characteristics have also been investigated disclosing the possibility of magnetic separation for the Fe2TiO5 material, making it an attractive candidate for application in the sustainable remediation of wastewaters.

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In the present work, we report, for the first time, the synthesis of a Cu–Ni-nanoalloy-based composite demonstrating remarkable magnetic activity as compared to that of the Ni nanoparticles. Apart from its possessing 3 times as much magnetic permeability as Ni powder, we have discovered unique properties exhibited by the product nanoparticles in the colloidal state in aqueous solutions. By applying an external magnetic field, a three-dimensional optical modulation with a transmission coefficient of 20–90% was observed.

The crystal structure, magnetic and transport properties, including resistivity and thermopower, of Ni50Mn18.75Cu6.25Ga25 and Ni49.80Mn34.66In15.54 Heusler alloys were studied in the (10-400) K temperature interval. We show that their physical properties are remarkably different, thereby pointing to different origin of their magnetostructural transition (MST). A Seebeck coefficient (S) was found to pass minimum of about-20µV/K in respect of temperature for both compounds. It was shown that MST observed for both compounds results in jump-like changes in S for Gabased compound and jump in resistivity of about 20 and 200 µΩcm for Ga and In-based compounds, respectively. The combined analyzes of the present results with that from literature show that the density of states at the Fermi level does not change strongly at the MST in the case of Ni-Mn-In alloys as compared to that of Ni-Mn-Ga.