Faculty of Materials Science and Applied Chemistry

We report on all-optical poling relaxation of E-O active dendrimers photo-patterned in the polycarbonate matrix. Three kinds of polyester type dendrimers G0, G1 and G2 containing azobenzene in the core were used as second-order nonlinear optical active chromophores to create noncentrosymmetry inside the material. We used a guest-host type system of these structures spin-coated on a glass substrate. These samples

Magnetic zinc ferrite (ZnFe2O4) nanopowders were synthesized using the sol–gel autocombustion method. X-ray diffraction (XRD) and scanning electron microscopy (SEM) measurements demonstrated that thermal decomposition of the 1-mm-thick xerogel layers in air formed monophasic spinel ferrite nanopowders with a particle size less than 30 nm. X-ray photoelectron spectroscopy (XPS) showed that the obtained reaction product contained antisite defects, with zinc ions occurring at the octahedral sites of the spinel structure. The concentration of antisite defects or inversion degree decreased when the relatively low annealing temperature was increased from 150 to 500 °C. Overall, the obtained ZnFe2O4, which is usually antiferromagnetic (exhibits no magnetic moment), demonstrated high saturation magnetization (60.7 emu g−1), and coercive force (56 Oe). This was due to the presence of the antisite defects in the structure.Magnetic zinc ferrite (ZnFe2O4) nanopowders were synthesized using the sol–gel autocombustion method. X-ray diffraction (XRD) and scanning electron microscopy (SEM) measurements demonstrated that thermal decomposition of the 1-mm-thick xerogel layers in air formed monophasic spinel ferrite nanopowders with a particle size less than 30 nm. X-ray photoelectron spectroscopy (XPS) showed that the obtained reaction product contained antisite defects, with zinc ions occurring at the octahedral sites of the spinel structure. The concentration of antisite defects or inversion degree decreased when the relatively low annealing temperature was increased from 150 to 500 °C. Overall, the obtained ZnFe2O4, which is usually antiferromagnetic (exhibits no magnetic moment), demonstrated high saturation magnetization (60.7 emu g−1), and coercive force (56 Oe). This was due to the presence of the antisite defects in the structure.