2. Articole
Permanent URI for this collectionhttps://msuir.usm.md/handle/123456789/47
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Item Magnetotransport properties of ultrathin LaMnO3 layers [Articol](Technical University of Moldova, 2011-07-07) Șapoval, Oleg; Belenciuc, Alexandr; Zasavițchi, Efim; Canțer, Valeriu; Moșneaga, VasiliiWe report the transport and magnetic properties of La-deficient ultrathin films of La1-MnO3 (LMO) grown on SrTiO3 (STO) and engineered by using different interfacial layers. LMO layer and adjusting interface oxide (LaO-STO and SMO) layers were grown by a metalorganic aerosol deposition technique with monolayer accuracy. The role of LaO-TiO2 interface in the formation of ferromagnetic metallic state in very thin LMO films was demonstrated. Ferromagnetic metallic ground state in LMO films with the thickness down to 6 monolayers is stabilized by a combination of a La-deficiency and the interface-induced doping.Item Thermal transport evolution due to nanostructural transformations in ga-doped indium-tin-oxide thin films [Articol](2021) Cocemasov, Alexandr; Brinzari, Vladimir; Jeong, Do-Gyeom; Korotcenkov, Ghenadii; Lee, Jong S.; Nika, Denis L.We report on a comprehensive theoretical and experimental investigation of thermal con- ductivity in indium-tin-oxide (ITO) thin films with various Ga concentrations (0–30 at. %) deposited by spray pyrolysis technique. X-ray diffraction (XRD) and scanning electron microscopy have shown a structural transformation in the range 15–20 at. % Ga from the nanocrystalline to the amorphous phase. Room temperature femtosecond time domain thermoreflectance measurements showed nonlinear decrease of thermal conductivity in the range 2.0–0.5 Wm−1 K−1 depending on Ga doping level. It was found from a comparison between density functional theory calculations and XRD data that Ga atoms substitute In atoms in the ITO nanocrystals retaining Ia-3 space group symmetry. The calculated phonon dispersion relations revealed that Ga doping leads to the appearance of hybridized metal atom vibrations with avoided-crossing behavior. These hybridized vibrations possess shortened mean free paths and are the main reason behind the thermal conductivity drop in nanocrystalline phase. An evolution from propagative to diffusive phonon thermal transport in ITO:Ga with 15–20 at. % of Ga was established. The suppressed thermal conductivity of ITO:Ga thin films deposited by spray pyrolysis may be crucial for their thermoelectric applications.Item Технология получения нанокомпозитных структур на основе ванадия и его окислов групповыми методами обработки [Articol](CEP USM, 2013) Прилепов, Владимир; Гашин, Петр; Заламай, Виктор; Кирица, AркадийEste dezvoltată tehnologia de obţinere a structurilor nanocompozite pe bază de oxizi de vanadiu, ceea ce permite folosirea metodelor de tratare în grup. Au fost studiate proprietăţile electrofizice ale nanocompozitelor obţinute. Se arată că structura straturilor subţiri de nanocompozit reprezintă o matrice dielectrică în bază de oxid de V2O5, în care sunt distribuite uniform clustere conductoare.Item Plasma treatment and surface sensibilization of tin dioxide films for enhancement of gas sensitivity [Articol](2005) Brînzari, Vladimir; Dmitriev, Serghei; Korotcenkov, GhenadiiThis paper presents result of investigation aimed at the improvement of gas sensitive properties of SnO2 thin film gas sensors (TFGS) by means of high frequency (HF) oxygen plasma treatment and its surface doping. Used in experiments SnO2 films were deposited by spray pyrolysis method. It is shown that plasma treatment provides 3-4 times growth of thin film gas sensitivity. Surface doping of SnO2 films with Pd leads to gas sensitivity increasing by order. It is conluded that combination of HF oxygen plasma treatment and surface sensibilization through surface doping is an effective way to considerable improvement of gas sensitive properties of tin dioxide based TFGS.Item Modeling of temperature regimes of thin film gas sensitive devices [Articol](2005) Dmitriev, SergheiThis paper presents results of the modeling of the temperature distribution in a chip of thin film gas sensor, operating at high temperatures (150-1000 oC), required to provide high sensitivity and selectivity to target gases. Analysis of thermal regimes of such chip was carried out on the base of model of plate with local source of heat. It was found that substrate heat conductivity is most influencing parameter, determining both temperature distribution in chip and also the electrical power consumption decreasing. The example of realized chips designed in accordance with results of modeling is presented. The results of modeling are compared with experimental data.