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The aim of the research was to investigate the influence of strontium on the structure of thin films La1-xSrxFeO 3 (x = 0; 0,1; 0,2). The LaFeO 3 and Sr-doped LaFeO3 films were produced by pulsed laser deposition (PLD) on Si (100) substrate using the Nd-YAG (λ = 266 nm) laser. SEM, AFM and XRD methods were used to characterize the structure and morphology of the thin films. X-Ray Diffraction analysis showed only the LaFeO 3 phase in the undoped thin film and the La0.9Sr0.1O 3 and La0.8Sr0.2O 3 phases in thin films doped by Sr. The mean crystallite size, calculated by Williamson-Hall method, was smaller (of the order of 18 nm) in films doped by Sr. SEM analysis showed small droplets in thin films doped by Sr. Highly developed surface layer was observed using the AFM microscope for thin films doped by Sr.Keywords: Perovskite LaFeO 3 , thin films, gas sensors, PLD on the surface structure of thin films by modification of process parameters. it were found optimal conditions for the deposition of nanocrystalline thin films of LaCoO 3 doped by Sr using laser ablation method. The study of the influence of Sr doping on the structure of LaFeO 3 thin films deposited by PLD is presented in this paper. Experimental Preparation of targetsThe undoped LaFeO 3 targets were purchased from the Kurt J. Lesker Company. The powders of La1-xSrxO 3 (x = 0.1, 0.2) were prepared by mechanical alloying method. The powders La1-xSrxO 3 multiphase La 2 O 3 , La(OH) 3 , La1-xSrxFeO 3 (x = 0, 0.1, 0.2) were milled in ball mill during t = 2, 4, 6, 10 hours using ZrO 2 balls. The powders were dried at temperature 973 K during 4 hours. Then, the targets were prepared by compacting the powders of La1-xSrxFeO 3 under a pressure of p = 10 9 Pa during 5 min then the pellets were sintered at T = 1623°K during 10 h. Deposition of thin filmsThe La1-x SrxCoO 3 (x = 0, 0.1, 0.2) thin films were deposited on (100) oriented Si substrate using a laser ablation system equipped with the Nd-YAG (266 nm) laser and the chamber

The aim of the presented investigations was to deposit the thin films La1−xSrxFeO3 (x = 0, 0.1, 0.2) on (100) Si substrate by using the Pulsed Laser Deposition (PLD) method. Structure was exanimated by using XRD, SEM, AFM, TEM and XPS methods. The catalytic properties were analyzed in 4 ppm acetone atmosphere. The doping of Sr thin films La1−xSrxFeO3 (x = 0, 0.1, 0.2) resulted in a decrease in the size of the crystallites, the volume of the elemental cell and change in the grain morphology. In the LaFeO3 and La0.9Sr0.1FeO3, clusters around which small grains grow are visible in the structure, while in the layer La0.8Sr0.2FeO3, the visible grains are elongated. The TEM analysis has shown that the obtained thin films had a thickness in the range 150–170 nm with triangular or flat column ends. The experiment performed in the presence of gases allowed us to conclude that the surfaces (101/020) in the triangle-shaped columns and the plane (121/200) faces in flat columns were exposed to gases. The best properties in the presence of CH3COCH3 gas were noted for LaFeO3 thin film with triangle columns ending with orientation (101/020).

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The aim of the presented research was to investigate the influence of strontium dopant on the structure and composition of La1−xSrxCoO3 (x = 0, 0.1, 0.2) perovskite thin films. Pure and Sr doped LaCoO3 thin films were grown by pulsed electron deposition technique on crystalline epi-polished Si/MgO substrates. Numerous analytical techniques (scanning electron microscopy, atomic force microscopy, X-ray photoelectron spectroscopy, and X-ray diffraction) were applied to characterize their phase/chemical composition, structure and surface morphology. X-ray diffraction analysis showed the presence of pure LaCoO3 perovskite phase in the undoped thin film. For Sr doped thin films La0.8Sr0.2CoO3 (x = 0.2), La0.9Sr0.1CoO3 (x = 0.1) small contents of La2 O3 and LaSrCoO4 phases were noticed. The crystallite sizes, calculated from the Williamson-Hall plots, were about 18 nm for all analyzed films. According to scanning electron microscopy/atomic force microscopy observations, obtained thin films were free from defects and cracks. Atomic force microscopy (tapping mode) analysis revealed the differences in the shape and quantity of surface crystallites for all thin films as a result of Sr doping and different deposition parameters. Atomic force microscopy technique also allowed measurement of roughness parameters for analyzed samples. X-ray photoelectron spectroscopy analyses of chemical states of elements of thin films showed that their chemical state was stable across the film thickness and even at the interface with the MgO substrate. X-ray photoelectron spectroscopy analysis also allowed to evaluate chemical states and atomic concentration of La, Co, and Sr elements within cross-sections of deposited thin films.