X-ray photoelectron spectroscopy analysis as a tool to assess factors influencing magnetic anisotropy type in Co/MgO system with gold interlayer

X-ray photoelectron spectroscopy (XPS) studies of Au/Co/Au(0.3 nm)/MgO and Au/Co/MgO systems were conducted in order to monitor the electronic structure modification at Co/MgO interface with/without gold interlayer. A detailed analysis of Co 2p states revealed that the amount of minor oxygen contribution at Co/MgO interface decreased after the Au interlayer was added. The obtained XPS results together with density functional theory (DFT) allowed explanation of the increase of surface anisotropy energy in the sample with the gold interlayer in terms of (i) noble and transitional metal d-d orbital hybridization; (ii) interfacial Co 3d and O 2p; and (iii) interface imperfectio

Evaporation of a small amount of gold onto polymers : effects on surface morphology and signal enhancement in static SIMS

In static secondary ion mass spectrometry (s-SIMS), several more or less sample-restraint methods of secondary ion yield enhancement have been proposed. One of those methods is called Metal-Assisted SIMS (MetA-SIMS) and consists in a deposition of a small amount of noble metal onto the organic sample in order to enhance the characteristic secondary ion fragment intensities. In contrast to other MetA-SIMS studies, the metallization of the high-mass polymers was carried out in a preparation chamber, which is directly connected to the ToF-SIMS. This in situ metallization allows reducing the surface contamination and atmospheric influences to a minimum during sample manipulation/transportation. Beyond the secondary ion yield enhancement measured in ToF-SIMS, the exact deposited gold quantity was determined by XPS and a detailed characterization of the sample surface was accomplished by SEM and TEM. The aim of this work was two folded: From a purely analytical point of view, it was tried to find out the optimal conditions for the metallization of various and widely used polymers in order to maximize the secondary ion intensities in MetA-SIMS. A more theoretical aspect was to get further fundamental insights in the secondary ion emission process in MetA-SIMS. By dint of the morphology results, a model explaining the observed yield enhancement of the characteristic polymer fragments during atomic primary ion bombardment for low gold coverage was developed. The model takes into account that the polymer quantity at the sample surface diminish due to the deposited gold and suggests that the secondary ion yield enhancement mainly occurs near the polymer/gold interface. However for larger gold coverage, additional factors need to be determined in order to completely describe the yield enhancement in ToF SIMS.(FSA 3) -- UCL, 201

Low-density polyethylene films treated by an atmospheric Ar-O2 post-discharge: Functionalization, etching, degradation and partial recovery of the native wettability state

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Composite polymeric-inorganic waveguide fabricated by injection molding for biosensing applications

Inorganic based optical transducers have demonstrated their suitability for labelled and label-free sensing of biomolecules but suffer from their relatively high cost. Photonic structures fabricated in polymer by molding techniques could drastically reduce the cost per test and pave the way for label-free screening in point-of care environment where the cost per test is an essential concern. In this paper we present the advances in the fabrication of waveguides with cyclo olefin copolymer (COC) cladding and TiO2 core with mass-production compatible injection molding and evaporation. We demonstrate the optical propagation in a slab waveguide supporting both transverse electric and magnetic modes and monitor the response of the phase difference between the two modes when a droplet of water is deposited on the chip

Experimental study of EUV mirror radiation damage resistance under long-term free-electron laser exposures below the single-shot damage threshold

The durability of grazing- and normal-incidence optical coatings has been experimentally assessed under free-electron laser irradiation at various numbers of pulses up to 16 million shots and various fluence levels below 10% of the single-shot damage threshold. The experiment was performed at FLASH, the Free-electron LASer in Hamburg, using 13.5 nm extreme UV (EUV) radiation with 100 fs pulse duration. Polycrystalline ruthenium and amorphous carbon 50 nm thin films on silicon substrates were tested at total external reflection angles of 20° and 10° grazing incidence, respectively. Mo/Si periodical multilayer structures were tested in the Bragg reflection condition at 16° off-normal angle of incidence. The exposed areas were analysed post-mortem using differential contrast visible light microscopy, EUV reflectivity mapping and scanning X-ray photoelectron spectroscopy. The analysis revealed that Ru and Mo/Si coatings exposed to the highest dose and fluence level show a few per cent drop in their EUV reflectivity, which is explained by EUV-induced oxidation of the surface

Experimental study of EUV mirror radiation damage resistance under long-term free-electron laser exposures below the single-shot damage threshold

The durability of grazing- and normal-incidence optical coatings has been experimentally assessed under free-electron laser irradiation at various numbers of pulses up to 16 million shots and various fluence levels below 10% of the single-shot damage threshold. The experiment was performed at FLASH, the Free-electron LASer in Hamburg, using 13.5 nm extreme UV (EUV) radiation with 100 fs pulse duration. Polycrystalline ruthenium and amorphous carbon 50 nm thin films on silicon substrates were tested at total external reflection angles of 20° and 10° grazing incidence, respectively. Mo/Si periodical multilayer structures were tested in the Bragg reflection condition at 16° off-normal angle of incidence. The exposed areas were analysed post-mortem using differential contrast visible light microscopy, EUV reflectivity mapping and scanning X-ray photoelectron spectroscopy. The analysis revealed that Ru and Mo/Si coatings exposed to the highest dose and fluence level show a few per cent drop in their EUV reflectivity, which is explained by EUV-induced oxidation of the surface