New interesting aspects of the spectroscopic properties, magnetism, and method of synthesis of gadolinium orthovanadates doped with Eu(3+) ions are discussed. Gd(1-x)Eu(x)VO4 (x = 0, 0.05, 0.2) bifunctional luminescent materials with complex magnetic properties were synthesized by a microwave-assisted hydrothermal method. Products were formed in situ without previous precipitation. The crystal structures and morphologies of the obtained nanomaterials were analyzed by X-ray diffraction and transmission and scanning electron microscopy. Crystallographic data were analyzed using Rietveld refinement. The products obtained were nanocrystalline with average grain sizes of 70-80 nm. The qualitative and quantitative elemental composition as well as mapping of the nanocrystals was proved using energy-dispersive X-ray spectroscopy. The spectroscopic properties of red-emitting nanophosphors were characterized by their excitation and emission spectra and luminescence decays. Magnetic measurements were performed by means of vibrating sample magnetometry. GdVO4 and Gd0.8Eu0.2VO4 exhibited paramagnetic behavior with a weak influence of antiferromagnetic couplings between rare-earth ions. In the substituted sample, an additional magnetic contribution connected with the population of low-lying excited states of europium was observed.

The first successful attempt to synthesize a new proton conducting polymeric nanocomposite film based on pure cellulose nanofibers (CNF) as a polymer matrix functionalized on their surface with imidazole molecules (Im) as a dopant, was made. The 2CNF-Im nanomaterial contains on average one molecule of imidazole per 2 glucose units from cellulose chains. Water evaporation and thermal stability of 2CNF-Im were studied by thermogravimetric analysis (TGA and DTG) and differential scanning calorimetry (DSC). The temperature dependence of electrical conductivity was studied by the impedance spectroscopy. At 140 °C, the 2CNF-Im nanocomposite has a maximum conductivity of 7.0 × 10−3 S/m, i.e. four orders of magnitude higher than that of non-functionalized CNF matrix. The newly synthesized cellulose nanocomposite exhibits high electrical and thermal stability. In 2CNF-Im, the activation energy of the proton transport process is the lowest compared to the previously synthesized imidazole-functionalized composites based on other pure cellulose materials and equals 0.62 eV. The synthesized nanomaterial is liquid-free solid polymer electrolyte showing proton conductivity above the boiling point of water.

The perpendicular exchange bias in NiO(antiferromagnet)/Co(ferromagnet) polycrystalline layer films is studied. It is found that the NiO layer forces the Co layer magnetization to be oriented perpendicular to the film plane in a greater thickness range than is found in the Au/Co/Au system. Simultaneously, a large coercivity and a significant perpendicular exchange bias field were observed that are owing to the interlayer exchange bias coupling between NiO and Co, which supports the perpendicular magnetic anisotropy of the Co layer. These findings are confirmed by magnetometry and magnetoresistance measurements.