D. Todorovsky

Spray pyrolysis deposition of α-Fe2O3 thin films using iron (III) citric complexes

Thin films of α-Fe2O3 have been deposited on fused silica substrates (heated at 500 °C) by an in situ spray pyrolysis method using ethylene glycol solution of Fe(III)-citric complexes and O2 as a carrier gas. The monophase composition of the films was confirmed by the X-ray diffractometry. Their morphology and roughness have been estimated by means of atomic force microscopy (AFM).

SiO2/polyester hybrid for immobilization of Ru(II) complex as optical gas-phase oxygen sensor

Organic–inorganic hybrid materials produced from tetraethoxysilane, citric acid and ethylene glycol in different mole ratios and consisting of Si–O–Si and Si–O–C nets are prepared and their molecular structure (IR and NMR spectroscopy), morphology (fluorescent microscopy, SEM and AFM), thermochemical behavior and fluorescence properties (excitation and emission spectra) are studied. The optically active, oxygen sensitive complex of tris(4,7-diphenyl-1,10-phenanthroline) ruthenium(II) dichloride is immobilized in the so prepared matrix and the applicability of the composite as an optical oxygen sensor (response to O2 in gaseous medium) is tested. The influence of the matrix composition on the linearity of the Stern–Volmer dependence and the films sensitivity to O2 is studied.

Highly Crystalline Y3Fe5O12 Thin Films by Cictric Spray Pyrolysis

Ethylene glycol solution of mixed-metal Y(III)-Fe(III) citric complexes has been used as a starting material for a spray pyrolysis deposition of Y3Fe5O12 (YIG) thin films on silica and on single crystal Y3Al5O12 (YAG) substrates heated up to 500°C. O2 was used as a carrier gas. A post-deposition thermal annealing at 800–1100°C was applied. Films of 0.1–1.2 μm in thickness were obtained. Their composition, binding energies, crystal structure, morphology, and magnetic properties were studied. Phase homogeneous polycrystalline or highly textured YIG films were obtained on silica or YAG substrates at annealing temperatures of 860° and 960°C, respectively. The crystallite grain sizes of both type of layers were ∼80 nm along the (400) plane. A columnar structure of the films with the column diameter of 400–500 nm might be supposed following the atomic force microscopy data. Saturation and permanent magnetizations along the easy axis of 1545 Gs and 816 Gs, respectively, and coercive force along the same axis of 4 Oe were measured.

Combined laser-magnetic field treatment of Y3Fe5O12 films grown by spray pyrolysis from Y-Fe citric complex initial solutions

Thin films (250 nm - 1200 nm) of cubic Y3Fe5O12 (YIG) were deposited on fused silica and monocrystal Y3Al5O12 (YAG) 100 substrates by spray pyrolysis (using ethylene glycol solutions of Y-Fe(III)-citric complexes) and additionally annealed at 950 degrees Celsius in static air for 2 h. The films were afterwards irradiated by a free-running Nd-YAG laser (pulse energy 650 mJ, pulse duration 700 microseconds, energy density 100 mJ/cm2) whose onset was synchronized with that of a magnetic field pulse of nearly-square shape (magnetic induction 0.5 T, pulse duration 900 microsecond). The samples were placed normally to the direction of the magnetic field. The temperature reached at the film surface was estimated to be as high as the melting point, considerably higher than the Curie temperature. The laser-magnetic field treatment causes: a sharp weakening of the YIG/YAG films texturation, highly textured before that treatment; an increase of the crystallites size; change in the phase composition of the YIG/silica films; an increase of the magnetization by more than 45%; an increase (in the case of YIG/silica) and decrease (in the case of YIG/YAG) of the coercive force.