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Temperature-dependent angle-resolved photoemission spectroscopy (ARPES) was carried out on single-crystalline EuB6samples. By measuring ARPES spectra in an extended Brillouin zone, we clearly observed a B 2phole pocket centered at the Xpoint, thus proving the semimetallic nature of EuB6. Below the Curie temperature TC, ARPES spectra show two B 2pbands of which separation is due to an exchange interaction between local Eu 4fand itinerant B 2pelectrons. The exchange splitting becomes smaller as the temperature increases and disappears well above TC. Additionally, a diffuse structure near the Fermi level survives at temperatures just above TC. Such behavior is well described by using Monte Carlo simulations of a Kondo-lattice model, thus supporting the formation of magnetic polarons in EuB6, which accounts for the resistivity upturn slightly above TCas the temperature is lowered.

Basing on the experimental results, obtained while studying both structural and gas sensing properties of the SnO2 and In2O3 films deposited by spray pyrolysis method, it was analyzed the influence of the crystallites size on the response of the SnO2-and In2O3-based thin film gas sensors. It was confirmed that that the grain size is one of the most important parameters of metal oxides, controlling almost all operating characteristics of the solid state gas sensors. However, it was shown that the decrease of the grain size is not a universal decision contributing to the improvement of sensor response. The decrease of the grain size could be accompanied either by the improvement, or the worsening of gas sensor operating characteristics.

A novel and effective methodology to control the diameters of semiconductor nanowires is reported through a versatile contact-printing method for obtaining size-controlled nanocatalysts by size-tunable carbon-based nanometer stamps. Vertically aligned carbon nanopost arrays, derived from nanoporous alumina templates, are used as the nanoscale stamps for printing of catalyst nanoparticles. The diameter of the carbon nanopost can be engineered by adjusting the pore dimension of the templates. Over the contact-printed Au nanodots in a uniform size distribution, semiconductor SnO2nanowires are grown viaa vapor−liquid−solid growth mechanism. Consequently, a direct dimension correspondence is achieved between the carbon nanopost stamp, the printed Au catalyst, and the finally obtained SnO2nanowires. A model example of the diameter-dependent electrical properties of the semiconductor nanowires is successfully demonstrated in this work by applying three diameter-controlled SnO2nanowires to nanowire field effect transistors.

New approach for the rational synthesis and surface functionalizing of SnO2 films aimed for gas sensors applications was discussed in this paper. It was shown that successive ionic layer deposition (SILD) technology due to its simplicity, low cost, and ability to control the deposition of nanolayers of various materials on rough surface can attract increased interest for those purposes.

Employing neutron and resonant x-ray scatterings, we have investigated the magnetic and structural phase transitions of a high quality single crystal of undoped pnictide EuFe2As2to reveal the nature of these transitions. It has been found that structural order parameter $\delta=(a-b)/(a+b)$ and the square of Fe magnetic order parameter have the same temperature dependence, which is attributed to the linear-quadratic coupling between structural and Fe magnetic order parameters in the Landau free-energy expansion. This result also suggests that Fe magnetic order drives the structural phase transition which is the weak first-order phase transition.