Search results for "Pulsed laser"
showing 10 items of 96 documents
Experimental and numerical assessment of subsurface plastic deformation induced by OFHC copper machining
2015
Strain distributions in the machined surface and subsurface of OFHC copper workpieces were determined experimentally and through numerical simulations. An experimental setup, comprising a double frame camera and a pulsed laser, was developed to measure the displacement fields using the digital image correlation (DIC) technique; strain distributions were then calculated. A numerical orthogonal cutting model was also developed and applied in order to predict such distributions. Comparison between simulated and measured results enabled an understanding of the fundamental mechanisms of plastic deformation of the machined surface of OFHC copper.; International audience; Strain distributions in t…
Defect detection in laser powder deposition components by laser thermography and laser ultrasonic inspections
2013
Laser Powder Deposition (LDP) techniques are being adopted within aerospace and automotive manufacturing to produce innovative precision components. Non-destructive techniques (NDT) for detecting and quantifying flaws within these components enables performance and acceptance criteria to be verified, improving product safety and reducing ongoing maintenance and product repair costs. In this work, software enabled techniques are presented for in-process analysis of NDT laser ultrasonic signals and pulsed laser thermography images of sequential metallic LPD layers. LPD tracks can be as thin as 200μm while deposited at a rate of 500 mm/min, requiring ultrafast inspection and processing times. …
Pulsed laser deposition of ZnO and VO2 films for memristor fabrication
2015
Memristors are resistive switching memory devices which have attracted much attention over the last years for high-density memory applications because of their simple structure, small cell size, high speed, low power consumption, potential for 3-D stacking and excellent compatibility with the complementary metal-oxide-semiconductor (CMOS) technology [1]. Beside nonvolatile memory applications, memristors have been also proposed for other different applications including biosensors [2] and neuromorphic [3] circuits. The device structure is simply an oxide material sandwiched between two metal electrodes. The switching behavior is not only dependent on the oxide material but also on the choic…
Density of States characterization of TiO2 films deposited by Pulsed Laser Deposition for Heterojunction solar cells
2021
The application of titanium dioxide (TiO2) in the photovoltaic field is gaining traction as this material can be deployed in doping-free heterojunction solar cells with the role of electron selective contact. For modeling-based optimization of such contact, knowledge of the titanium oxide defect density of states is crucial. In this paper, we report a method to extract the defect density through nondestructive optical measures, including the contribution given by small polaron optical transitions. The presence of both related to oxygen-vacancy defects and polarons is supported by the results of optical characterizations and the evaluation of previous observations resulting in a defect band …
<title>Irradiation effects in lead zirconate thin films</title>
2003
Lead zirconate PbZrO3 (PZ) and PbZr0.53Ti0.47O3 (PZT) sol-gel films with a thickness of up to 1.5 μm were deposited on TiO2/Pt/TiO2/SiO2/Si substrates by spin coating technique and heterostructures of the same composition as well as on Pb0.92La0.08 (Zr0.65Ti0.35)O3 (PLZT-8) (with a thickness of 0.4 μm) were pulse laser deposited (PLD) on Pt/Ti/SiO2/Si. Observation of a typical antiferroelectric (AFE) double hysteresis loop in obtained PZ heterostructures at room temperature was attributed to the superior dielectric strength in case of thin film materials. The thermal behavior of dielectric permittivity e of PZ film reveals a maximum near 225°C on heating and 219°C on cooling. The higher res…
Analysis of Transition Metal Oxides based Heterojunction Solar Cells with S-shaped J-V curves
2020
The use of transition metal oxides for the selective carrier contact in the crystalline silicon solar cells technology is rising to interest for the excellent optoelectrical properties of these materials whose implementation, however, can result in lousy performing cells due to an S-shaped electrical characteristic. In this paper, we fabricated solar cells showing S-shaped J-V curve and carried out an analysis of the reasons of such behavior using a model involving the series of a standard cell equivalent circuit with a Schottky junction in order to explain these atypical performances. A good matching between the experimental measurements and the adopted theoretical model was obtained. The …
Preparation and characterization of (Hg0.7Mo0.3)Sr2(Ca0.7Y0.3)Cu2Ox and (Hg0.9Re0.1)Ba2CaCu2Oy superconducting films by laser ablation
2000
Abstract Oriented (Hg 0.7 Mo 0.3 )Sr 2 (Ca 0.7 Y 0.3 )Cu 2 O x and (Hg 0.9 Re 0.1 )Ba 2 CaCu 2 O y superconducting films were prepared on SrTiO 3 substrates using laser ablation and post-Hg-vapor annealing. Due to the stability of Mo 0.3 Sr 2 (Ca 0.7 Y 0.3 )Cu 2 O x and Re 0.1 Ba 2 CaCu 2 O y in air, no special handling was needed during the grinding, mixing and pressing of the precursor targets. The superconductivity of the films was characterized with the temperature dependence of the ac susceptibility ( χ - T ) and the resistance ( R - T ) while the crystallography was probed with x-ray diffraction (XRD) and scanning electron microscopy (SEM).
Resistivity and irreversibility line of (Hg0.9Re0.1)Ba2CaCu2O6+δ HTS thin films
2003
Abstract High-quality epitaxial (Hg 0.9 Re 0.1 )Ba 2 CaCu 2 O 6+ δ HTS thin films were successfully prepared by pulsed laser deposition (PLD) of Hg-free precursor material on (1 0 0)-oriented SrTiO 3 substrates with subsequent Hg vapour annealing. (Hg 0.9 Re 0.1 )Ba 2 CaCu 2 O 6+ δ HTS thin films exhibit sharp superconducting transitions at T c ≈122 K. The electrical resistance for c -axis oriented HgRe-1212 films has been studied as a function of temperature and dc magnetic fields up to 10 T parallel to the crystallographic c -axis. The irreversibility line for the HgRe-1212 has been deduced from the data and investigated as a function of reduced temperature T / T c . The result of the irr…
Normal and mixed state Hall effect in (Hg0.9Re0.1)Ba2CaCu2O6+δ fully textured HTSC thin films
2004
Abstract Temperature and magnetic field dependence of the Hall effect in the normal and mixed state of fully textured (Hg0.9Re0.1)Ba2CaCu2O6+δ (HgRe-1212) HTSC thin films prepared by laser ablation deposition have been studied. The longitudinal resistivity ρxx and Hall resistivity ρyx of HgRe-1212 superconductor thin films were measured for a wide range of magnetic fields from 125 mT to 12 T with the field perpendicular to the ab plane and the current in the ab plane. A sign change of the Hall resistivity is observed in fields below 3 T in the region close to the superconducting onset temperature. The temperature dependencies ρxx ∝ T and ρyx ∝ 1/T have been observed for HgRe-1212 thin films…