Solid State Phenomena Vol. 245

Abstract: The coatings manifesting ferromagnetic characteristics have been formed on titanium and aluminum by plasma electrolytic oxidation (PEO) in alkaline electrolytes additionally containing iron oxalate and cobalt or nickel acetate. The metals of iron subgroup are found to be concentrated in pores of PEO coatings, as a rule, in form of crystallites. In a number of cases the relation between crystallite compositions and magnetic properties of the coatings has been established.

Abstract: This paper presents the results of the study of chitosan-metal nanofilms for the formation of submicron structures on glass substrates by electron lithography. The dependence of their basic lithographic characteristics from the selection of the metal for intermediate layer is obtained.

Abstract: The conditions of formation of the ZrO₂ and HfO₂ high-temperature (tetragonal and cubic) phases in the ablated nanoparticles were investigated. X-ray diffraction and transmission electron microscopy data demonstrate that laser intensities above 10⁹ W/m² ensure the formation of the ZrO₂ high-temperature phases, while intensities above 5·10⁹ W/m² do the formation of the HfO₂ high-temperature phases. Quantitative content of the high-temperature phases in layers of the ablated nanoparticles increases with raising the intensity. The obtained nanoparticles exhibit good thermal stability.

Abstract: The effect of amines and ammonia vapour on luminescence of Eu (III) complexes immobilized in different matrices has been investigated. It has been revealed that interaction of Eu (III) tris-dibenzoylmethanate with analyte vapour results in the increase of the intensity of Eu (III) luminescence. The mechanism of the effect of ammonia and amines vapours on intensification of the Eu (III) luminescence has been suggested using the data of IR, luminescence spectroscopy and quantum chemistry calculations.

Abstract: The results of the experimental study of the critical X-ray scattering (CS) in PbZr_0.6Ti_0.4O₃ (PZT40) single-crystal are presented. Temperature evolution of the CS lineshape and intensity was analyzed. It is demonstrated that CS can be described in terms of the mean-field model. Temperature dependences of the peak intensity of the CS, proportional to the static susceptibility, and the correlation length of the «ferroelectric fluctuations» follow the Curie-Weiss law with the Curie temperature T_c=638 K. Obtained results confirm the second-order character of the phase transition in the PZT40.

Abstract: An experimental study of low temperature domain dynamics could provide information on a mechanism of domain wall motion at low temperatures in thin ferroelectric films. For this purpose we use a piezoresponse force microscopy (PFM) technique and investigate the 180⁰ ferroelectric domains growth in the temperature range 5 K – 295 K. Domains were created by applying a dc voltage pulses between an atomic force microscopy (AFM) tip and a bottom electrode of a thin epitaxial PbZr_0.3Ti_0.7O₃ film. Two different types of tips were used, a semiconducting tip with dopant conductivity and a tip with metallic coating to clarify an influence of poling procedure on the domain dynamics. Created domains were then visualized and their in-plane sizes were measured with out-of-plane PFM. Dependences of lateral domain size on the duration and amplitude of dc voltage pulse were obtained. Received experimental dependences were then fitted with logarithmic function with good accuracy. This circumstance indicates on the thermally activated mechanism of domain growth and formation. Temperature dynamics of the 180⁰ ferroelectric domains growth does not depend on the AFM tip used in a poling procedure what allows us to conclude that the voltage transfer to the ferroelectric film does not significantly depend on the tip-film local contact properties.

Abstract: This paper presents the study results of morphology contact and free surface at amorphous metal foils (Fe₇Co₇₁Ni₁₂(SiB)₁₀, Fe₇₀Ni₁₀(SiB)₁₀, Fe₆₀Co₃₀(SiB)₁₀) and their analysis of the elemental composition. Using spectral methods of research was allowed to make a comparative analysis size and anisotropy of distribution topological inhomogeneities. A parallel study of spinning foils by Mossbauer spectroscopy and Vibrating sample magnetometer (VSM) possible to determine the magnetic state of the samples.

Abstract: The article discusses the formation of coatings with magnetic properties on non-magnetic substrates by the method of additive technology of metal powders using high power pulsed laser radiation. An instrumental base for the development of methods for creating local magnetic zones of a given configuration has been described. Approaches to create methods of additive welding of solid solution magnetic zones on the basis of micro-powders of metal alloys have been developed. The coatings with soft magnetic properties on the basis of powders of bronze and iron-containing "Inconel" alloy on non-magnetic substrates were obtained by laser welding. The structural inhomogeneity at the interface of the substrate and the solid solution were studied. Data on hardness and magnetic properties were obtained for formed magnetically soft materials.

Abstract: New data on the structure of silicon-containing oxide layers SiO₂+TiO₂ on titanium formed by the method of plasma electrolytic oxidation (PEO) as well as on the structure and catalytic activity in CO oxidation of MnO_x+SiO₂+TiO₂/Ti composites formed on their basis using impregnation and annealing methods have been obtained. It has been demonstrated that silicon and titanium are rather homogeneously distributed over the SiO₂+TiO₂ coating bulk. The coating outer part is silicon-enriched titanium-depleted. The MnO_x+SiO₂+TiO₂/Ti composites catalyze the CO conversion at temperatures above 100°C. Nanowhiskers consisting predominantly of manganese oxides have been found on the surface of the MnO_x+SiO₂+TiO₂/Ti composites.

Abstract: Here we present a simple technique for copper (II) detection in aqueous solutions by luminescent dye doped polymeric film. In this study the photoluminescent dye lumocupferon was first embedded in thin films of polysaccharide chitosan. The sensor response is forming by quenching the dye luminescence. This technique can offer a rapid detection of Cu²⁺ with a dynamic range up to 350 μM.