Effect of pressure on magnetic properties of magnetic nanoparticles, based on Prussian blue analogues, were studied in pressures up to 1.2 GPa. The Mn 3 [Cr(CN) 6 ] 2 · nH 2 O and Ni 3 [Cr(CN) 6 ] 2 · nH 2 O nanoparticles were prepared by reverse micelle technique. Transmission electron microscopy images show nanoparticles with average diameter of about 3.5 nm embedded in an organic matrix. The characteristic X-ray peaks of nanoparticles are more diffused and broader. Systems of nanoparticles behave as systems of interacting magnetic particles. The Curie temperature TC is reduced from T C = 56 K for Ni-Prussian blue analogues to T C = 21 K for Ni-nanoparticles system and from TC = 65 K for Mn-Prussian blue analogues to T C = 38 K for Mn-nanoparticles system. One can explain this reduction of the Curie temperature and of the saturated magnetization µs by dispersion of nanoparticles in an organic matrix i.e. by a dilution effect. Applied pressure leads to a remarkable increase in T C for system of Mn-nanoparticles (∆T C /∆p = +13 K/GPa) and to only slight decrease in T C for system of Ni-nanoparticles (∆T C /∆p = −3 K/GPa). The pressure effect follows behavior of the mother Prussian blue analogues under pressure. The increase in saturated magnetization, attributed to compression of the organic matrix, is very small. PACS numbers: 75.30.Cr, 75.50.Ee, 75.50.Gg, 75.50.Xx (489) 490 A. Zentko et al.

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Precise research on the RbF–Al2O3 system was carried out by means of combining X-ray powder diffraction, high-field solid-state NMR spectroscopy, and thermal analysis methods. α-Rb3AlF6, RbAlO2, Rb2Al22O34, and new phase, Rb2Al2O3F2, were identified in the system. The structure of this new rubidium oxofluoroaluminate was determined. It is built up from single layers of oxygen-connected AlO3F tetrahedra, those layers beeing separated by fluorine atoms. This type of structure exhibits a decent ionic conductivity at ambient temperature, 1.74 × 10–6 S cm–1. The similar structural arrangement of O3Al–O–AlO3 and FO2Al–O–AlO2F tetrahedra of the conduction planes in Rb2Al22O34 and Rb2Al2O3F2 were confirmed by 27Al NMR measurements. A thermal analysis of the RbF–Al2O3 system revealed that it can be defined as a pseudobinary subsystem of the more general quaternary RbF–AlF3–Al2O3–Rb2O phase diagram. From a phase analysis of individual phase fields, the mutual metastable behavior of all founded phases can be considered. It was observed that fluoro- and oxoaluminates exist together. Rb2Al2O3F2 is more stable under high temperature. Rubidium fluoro- and oxoaluminates are metastable precursors of the thermodynamically more stable structure of rubidium oxofluoroaluminate.

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Large scale production of single crystalline phase of Heusler Co 2 FeSi alloy microwire is reported. The long microwire (~ 1 km) with the metallic nucleus diameter of about 2 µm is characterized by well oriented monocrystalline structure (B2 phase, with the lattice parameter a = 5.615 Å). Moreover, the crystallographic direction [101] is parallel to the wire´s axis along the entire length. Additionally, the wire is characterized by exhibiting a high Curie temperature (Tc > 800 K) and well-defined magnetic anisotropy mainly governed by shape. Electrical resistivity measurement reveals the exponential suppression of the electron-magnon scattering which provides strong evidence on the half-metallic behaviour of this material in the low temperature range.

Magnetization measurements performed on Prussian blue analogs Mn, Fe, Co, Ni, Cu) confirmed the dual character of the exchange interaction (antiferromagnetic AFM and ferromagnetic FM) in this system. AFM interaction dominates for the Cr 2+ sample and with rising atomic number Z the FM interaction becomes more important reaching pure FM character for the Cu 2+ sample.

In this study, we have prepared PLGA (poly-D,L-lactide-co-glycolide) nanospheres loaded with biocompatible magnetic fluid and anticancer drug taxol by a modified nanoprecipitation technique and investigated their magnetic properties. A magnetic fluid, MF-PEG, with a biocompatible layer of polyethylene glycol (PEG), was chosen as a magnetic carrier. The PLGA, whose copolymer ratio of D,L-lactide to glycolide is 85:15, was utilized as a capsulation material. Taxol, as an important anticancer drug, was chosen for its significant role against a wide range of tumours. The morphology and particle size distributions of the prepared nanospheres were investigated by transmission electron microscopy (TEM) and scanning electron microscopy (SEM) and showed a spherical shape of prepared nanospheres with size 250 nm. Infrared spectroscopy (FTIR), differential scanning calorimetry (DSC) and thermogravimetry (TGA) analysis confirmed incorporation of magnetic particles and taxol into the PLGA polymer. The results showed good encapsulation with magnetite content 21.5 wt% and taxol 0.5 wt%. Magnetic properties of magnetic fluids and taxol within the PLGA polymer matrix were investigated by SQUID magnetometry from 4.2 to 300 K. The SQUID measurements showed superparamagnetism of prepared nanospheres with a blocking temperature of 160 K and saturation magnetization 1.4 mT.

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