X-Ray and ultraviolet photoelectron spectroscopy studies of Uranium(iv),(v) and(vi) exposed to H2O-plasma under UHV conditions

We report surface characteristics of UO2, U2O5 and UO3 thin films after exposure to gas plasmas: a new approach of the oxidative dissolution problem.

HAFNIUM AND NITROGEN INTERACTION AT Hf/GaN(0001) INTERFACE

The growth and stability of hafnium films on [Formula: see text]-GaN(0001) surface with native oxide was investigated with X-ray and ultraviolet photoelectron spectroscopy (XPS, UPS). It is shown that hafnium creates a continuous and stable layer on GaN substrate. Thermal treatment at [Formula: see text]C of Hf/GaN system causes decomposition of GaN and reaction of hafnium with atomic nitrogen from the substrate. XPS spectra demonstrate the reaction by a strong shift of the N 1s and Hf 4f lines. An attempt for bringing on the same reaction with molecular nitrogen under pressure of [Formula: see text] mbar was not successful. UPS spectra show a metallic character of the hafnium adlayer in such instances.

Tuning the Magnetism of Gold Nanoparticles by Changing the Thiol Coating

<div>Room-temperature ferromagnetic behaviour has been reported in nanoscaled materials excepted to be diamagnetic, including gold. However, it is yet unclear which factors (size, shape, surface coating) predominantly influence the magnitude of the magnetic response. In this work, we study the magnetic and electronic properties of similarly-sized gold nanoparticles (Au NPs) coated with four different n-alkanethiols, as well as hydroxyl- and carboxyl-functionalized alkanethiols using superconducting quantum interference device (SQUID) magnetometry and ultraviolet photoelectron spectroscopy (UPS). We find room-temperature behaviour (hysteresis in magnetization vs field strength loops) in all samples, as well as large effective magnetic anisotropy. Importantly, we find the nanoparticles coated with polar chain end-groups (-OH and -COOH) show markedly higher magnetization; this increased magnetization correlates with a higher work function. This work establishes chemical handles to enhance magnetism in nanoscale gold particles.</div>