In this work, spinel ferrites (NiCoFe2O4) were prepared as thin films by dc reactive dual-magnetron co-sputtering technique. Effects of some operation parameters, such as inter-electrode distance, and preparation conditions such as mixing ratio of argon and oxygen in the gas mixture, on the structural and spectroscopic characteristics of the prepared samples were studied. For samples prepared at inter-electrode distance of 5 cm, only one functional group of OH- was observed in the FTIR spectra as all bands belonging to the metal-oxygen vibration were observed. Similarly, the XRD results showed that decreasing the pressure of oxygen in the gas mixture lead to grow more crystal planes in the samples prepared at inter-electrode distance of 5 cm. The energy band gap was determined for the sample prepared with mixing ratio of 65:35 and found to be 2.7, 2 and 3.35 eV for direct allowed, direct forbidden and indirect allowed transitions, respectively. The high structural purity was confirmed as no traces for any elements other than Co, Ni, Fe and O were found in the final samples.

In this work, luminescent complex, terbium (III) bdiketonate (C 24 H 16 F 9 O 8 S 3 Tb), was prepared and incorporated into silica matrix by ordinary sol-gel method. The starting precursor which provide silica matrices was tetraethyl orthosilicate (SiOC 2 H 5 ) 4 . The experimental conditions have been adopted, so that the sample formation via sol-gel route was started at neutral pH, whereas the final pH value was normalized to three before reaching gel point. The spectroscopic analysis of terbium b-diketonate complexes-based xerogel matrices as a function of Tb ?3 concentrations has been realized using UVvisible absorption, (FTIR) spectroscopy and luminescence measurement. The luminescence behavior of Tb 3? ions can be improved in such matrices. The complex can be incorporated into the silica matrix at the same time as the hydrolysis and condensation reaction of the silanes start. The green emission of Tb 3? ions at 544 nm was clearly observed and indicates the good stability of Tb complex in silica sol-gel matrices. Graphical AbstractKeywords Sol-gel Á Silica matrix Á Terbium b-diketonate complex Á Luminescence