Search results for "pulsed laser deposition"
showing 10 items of 76 documents
Comparison of LIBS results on ITER-relevant samples obtained by nanosecond and picosecond lasers
2019
This work has been carried out within the framework of the EUROfusion Consortium and has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement number 633053. The views and opinions expressed herein do not necessarily reflect those of the European Commission. Work performed under EUROfusion WP PFC.
Stability/Instability of Conductivity and Work Function Changes of ITO Thin Films, UV-Irradiated in Air or Vacuum. Measurements by the Four-Probe Met…
2001
This study shows that, after UV-irradiation in air or vacuum, conductivity and work function of ITO and In2O3 come back to their initial values in a few hours or minutes. In addition to this instability, one of the reported drawbacks of ITO is the indium diffusion into the organic layers of operating LED, leading to performance degradation. So, we have reconsidered ITO as transparent anode and explored alternatives such as NiO.
Structure and properties of epitaxial ferroelectric PbLu0.5Nb0.5O3thin films
2001
Abstract Epitaxial thin film heterostructures of PbLu0.5Nb0.5O3 (PLuN) and La0.5Sr0.5CoO3 (LSCO) were deposited by in situ pulsed laser ablation onto MgO and LaAlO3 (100) substrates. The formation of crystalline phases, epitaxy, film-electrode-substrate orientation relationships, crystal perfection and chemical order were studied by x-ray diffraction. The structural properties were found to depend on the deposition conditions and on the substrate. The perovskite PLuN films were pseudocubic and epitaxial, with (001) planes parallel to the substrate surface. At room temperature, Au/PLuN/LSCO capacitors exhibited ferroelectric behavior and zero-field dielectric permittivity about e ≅ 210–260, …
Compositional Evolution of Properties in Epitaxial Films of Relaxor PbMg1/3Nb2/3O3-PbTiO3
2005
Epitaxial heterostructures of relaxor (1− x) PbMg1/3Nb2/3O3−(x) PbTiO3 thin films with La0.5Sr0.5CoO3 bottom electrodes were grown by pulsed laser ablation on MgO substrates. Perovskite films with x = 0–0.32 were deposited using sub-monolayer mixing from two targets. Both the room-temperature studies of microstructure and studies of dielectric response as a function of frequency and temperature were performed. For all x, a relaxor-like behavior was observed. The compositional evolution of lattice parameter, permittivity, and temperature of dielectric maxima T m was in a qualitative agreement with that in bulk. The relatively low temperatures T m in the presence of an in-plane compression we…
Some New Ceramics and Thin Films of Pb(B 3+ ,Nb)TiO 3 -PbTiO 3 System
2002
The structure, dielectric, and electromechanical properties of (1-x)Pb(B 3+ ,Nb)TiO 3 -xPbTiO 3 binary systems (B=Lu,Er,To,Ho) are reported. High values of the electromechanical coupling coefficien...
Oxide or carbide nanoparticles synthesized by laser ablation of a bulk Hf target in liquids and their structural, optical, and dielectric properties
2016
International audience; Laser ablation of a bulk Hf target in deionized (DI) water, ethanol, or toluene was carried out for the production of nanoparticles' colloidal solutions. Due to the interaction of the ablation plasma plume species with the species which are produced by the liquid decomposition at the plume-liquid interface, hafnia (HfO2) nanoparticles are synthesized in DI water, hafnium carbide (HfC) nanoparticles in toluene, and a mixture of these in ethanol. The hafnia nanoparticles are in the monoclinic low temperature phase and in the tetragonal and fcc high temperature phases. Their size distribution follows log-normal function with a median diameter in the range of 4.3–5.3 nm.…
Pulsed laser deposition of relaxor ferroelectric films
1998
Heterostructures of perovskite relaxor ferroelectric (RFE) thin films onto La 0.5 Sr 0.5 CoO bottom electrode layers were grown by pulsed laser deposition on MgO(100) crystal substrates. The films were highly oriented, with (h00) planes parallel to the substrate surface, and demonstrated good dielectric and ferroelectric quality at room temperature. The studies of the dielectric properties of the films over the frequency range of 20 Hz....100 kHz and over the temperature range of 0...350°C revealed relaxor type behavior in the films. A diffuse ferroelectric phase transition and a shift of the maximum dielectric permittivity towards higher temperatures with increasing frequency were observed…
Ceramics and Thin Films of Some New Pb(B 3+ ,Nb)TiO 3 -PbTiO 3 Systems
2003
The structure, dielectric, and electromechanical properties of (1 m x )Pb(B 3+ ,Nb)TiO 3 - x PbTiO 3 binary systems (B = Lu, Er, Tb, Ho) are reported. The crystallographic features at the morphotropic phase boundary (MPB) between tetragonal P4mm and pseudo-monoclinic M phases are discussed with respect to electro-mechanical properties. Doping effect (with La 3+ ) on the properties of ceramic samples of pseudobinary Pb(Lu 1/2 Nb 1/2 )O 3 -PbTiO 3 (PLuNT) system has been investigated. Pb(Mg 1/3 Nb 2/3 )-PbTiO 3 (PT) solid solutions were studied under different processing conditions for obtaining ceramics of 100% perovskite structure with sufficient high j T EC ∼ 1 K near room temperature. The…
Epitaxial growth and properties of (001)-oriented TbBaCo2O6−δ films
2008
Thin epitaxial films of TbBaCo2O6−δ cobaltites have been synthesized using pulsed laser deposition. It was found that the film properties are extremely sensitive to the oxygen pressure during deposition, temperature of the substrate, and the cooling rate. Growth parameters were optimized for δ≈0.5 films with ordered Tb and Ba ions, as well as oxygen vacancies. The properties of these c-axis oriented films are similar to bulk TbBaCo2O5.5: they show a metal-insulator phase transition at TMI≈350 K, ferromagnetic order below TC=285 K, and antiferromagnetism at T<Ti≈230 K.
Spectroscopic ellipsometry applied to phase transitions in solids: possibilities and limitations
2009
The possibilities of in situ spectroscopic ellipsometry applied to phase transitions investigation in oxide thin films and crystals are examined in this work, along with the use of various parameters calculated from ellipsometric data (band gap energy Eg, refractive index n and surface roughness) together with the directly measured main ellipsometric angles psi and Delta, for the detection of phase transitions. The efficiency of spectroscopic ellipsometry on "surface" phase transition and its sensitivity to surface defects are also demonstrated.