Innovative procedure for synthesis of anisotropic superparamagnetic nanostructures was developed in the cooperation with our spin-out company Nanos SCI. The synthesis is based on dynamic magnetic assembly of superparamagnetic nanoparticle clusters in suspensions into chain-like hierarchical structures and their simultaneous disintegration induced by shear forces of mixing. The procedure is capable of synthesizing magnetic nanochains of defined lengths. The nanochains are believed to be important materials enabling entirely new approach in the treatment of cancer.
COBISS.SI-ID: 28882727
Bi-magnetic, platelet nanoparticles combining a hard-magnetic Ba-hexaferrite (BaFe12O19) platelet core in between two soft-magnetic iron oxide maghemite (-Fe2O3) layers were presented for the first time. The nanoparticles were synthesized using a new, simple and inexpensive method based on the co-precipitation of Fe3+/Fe2+ ions in a colloidal aqueous suspension of the hexaferrite core nanoparticles. The hexaferrite displays the highest magnetocrystalline anisotropy from all magnetic oxides, however, modest saturation magnetization. By combining the hexaferrite core with the soft magnetic shell in single nano-unit, the saturation magnetization can be strongly increased. Moreover, the topotactic growth of the maghemite shell on the hexaferrite core supported the direct magnetic coupling between the core and the shell, resulting in a large increase of the remanence and, as a result, of the energy product BHmax , a figure of merit for the quality of permanent magnets (for more than twice compared to the core alone).
COBISS.SI-ID: 28332071
This article addresses for the first time an issue of the dissolution of nanoparticles, specifically fluorescent upconverting nanoparticles based on binary and ternary rare-earth fluorides, which have been proposed as alternative bio-markers in medical diagnostics. Our results show a significant dissolution of these nanoparticles in water and its dependence on chemical composition, crystal structure and nanoparticle size. The observed dissolution questions the aaplicability of these nanoparticles in bio-medicine.
COBISS.SI-ID: 28445735
A successful preparation of stable suspensions of barium hexaferrite nanoplatelets enabled their homogeneous distribution in the PMMA polymer matrix. The article reports on the preparation of a transparent composite with anisotropic magnetic and optical properties, which at the same tima shows a significant magneto-optic coupling. This new material is suitable for various magneto-optic elements.
COBISS.SI-ID: 18777878
Composite nanoparticles can be synthesized by assembly of two different nanoparticles (hetero-agglomeration) in the suspension. The hetero-aggregation can be induced by applying an attractive electrostatic force between nanoparticles with an opposite surface charge or the chemical reactions between surface molecules. In this article, the two types of interactions were directly compared in the system composed of maghemite nanoparticles grafted by silane molecules with terminal carboxyl groups (a negative surface charge in the aqueous suspension), and silica nanoparticles with terminal amino groups (a positive surface charge). The hetero-agglomeration using the chemical interactions between the nanoparticles resulting from direct reactions between the amino and carboxyl groups of the molecules at their surfaces appeared to be more efficient compared to hetero-agglomeration using electrostatic interactions.
COBISS.SI-ID: 28068647