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Abstract: The magnetic and magneto-optical properties of Al ∕ Co ∕ V ∕ Mg O ( 100 ) structures and the influence of the Co ∕ V interface for different thicknesses of the Co and V layers have been studied experimentally. From the element-specific hysteresis loops obtained by x-ray magnetic circular dichroism (XMCD) at the Co and V L 3 edges we find that the V layers are magnetically polarized antiparallel to the Co layers and that magnetization reversal occurs at the same magnetic field in both layers. The effect of the V atomic volume and the relative thicknesses of V and Co layers on the magnetic moments of the V and Co atoms are also studied. Contrary to what might be expected, the atomic magnetic moments of the V and Co atoms do not depend on the V atomic volume, however they depend strongly on the thicknesses of the V and Co layers. From the trend in the Co and V atomic magnetic moments as a function of Co and V thicknesses and the absence of any spectroscopic evidence for the formation of a VCo alloy, a long-range spin polarization of the V atoms is proposed. The extracted magneto-optical (MO) constants of V and Co as a function of photon energy clearly evidence a large amount of polarization in the V films in agreement with the XMCD results, which is indicative of the magnetic coupling between Co and V. The experimental MO results and simulations also show the strong influence of these polarized V layers in the MO properties of the complete system. These results, given the absence of spectroscopic evidence for the formation of a VCo alloy, support a long-range magnetization of the V atoms and a reduction of the Co atomic magnetic moments.

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Abstract: Gold nanoparticles with a polymer coating exhibiting large and reversible thermoresponsiveness are prepared via a one-pot synthesis method using narrow polydispersity thermoresponsive block copolymers.

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Abstract: Energy dispersive extended X-ray absorption fine structure spectroscopy (ED-XAFS), diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) and mass spectrometry (MS), have been combined for the structure–function study of Rh and RhPd supported catalysts for the reduction of NO by CO. The combined results show that although alloying of Rh with Pd prevents the dissociative oxidation of the Rh by NO, it does not prevent the extensive disruptive oxidation of Rh by CO. The influence of oxidative disruption by molecular CO in such systems may therefore be far more pervasive and catalytically important than has been previously observed. The overall metal particle size observed in the RhPd alloy system during the CO/NO reaction is significantly larger than for the Rh-only system for the entire temperature range employed. The catalytically active sites, however, are likely to be similar, with the overall activity of the alloy system to be reduced due to inactive RhPd alloy nanoparticles.

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Abstract: We studied the plastic deformation of a Cu monochromator loaded in tension along the [I 10] direction between 0 and 4% equivalent shear strain. We tracked the changes in the orientation and mosaicity of the specimen at several locations simultaneously by analysing the neutron spectra transmitted by the sample. We found that an initial misalignment between different regions of the specimen decreases as deformation proceeds, to reach a minimum at 2% shear strain. On the other hand, the mosaicity of most reflections changes linearly from 10 to 30 min, except for the [2 0 0] reflection, which presents a more complex behaviour.The experiments used a novel transmission technique involving a polychromatic neutron beam and a pixellated time of flight detector. The technique exploits sharp dips in intensity present in the transmitted neutron spectrum, corresponding to the neutrons removed from the beam after being diffracted by the crystal planes.

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Abstract: High-resolution x-ray and neutron powder-diffraction measurements were performed on polycrystalline VOMoO4. Below similar or equal to 40 K the system orders in a simple Neel antiferromagnetic state (propagation vector k=0), indicating a dominant role of the nearest-neighbor interactions. The order is three dimensional but the reduced saturated magnetic moment m of 0.41 (1) mu(B)/V4+ at 2 K indicates strongly two-dimensional character and enhanced quantum fluctuations. On cooling, there is no evidence of a reduction of the crystal symmetry. However, neutron diffraction indicates an anomalous evolution of the lattice parameters, which can be related to the onset of magnetic correlations.