The origin of the anomalous, 400% increase of the piezoelectric coefficient in Sc(x)Al(1-x)N alloys is revealed. Quantum mechanical calculations show that the effect is intrinsic. It comes from a strong change in the response of the internal atomic coordinates to strain and pronounced softening of C33 elastic constant. The underlying mechanism is the flattening of the energy landscape due to a competition between the parent wurtzite and the so far experimentally unknown hexagonal phases of the alloy. Our observation provides a route for the design of materials with high piezoelectric response.

Due to the very limited availability of B 4 C targets in an Ar discharge, using an industrial deposition system. The films were characterized with scanning electron microscopy, elastic recoil detection analysis, x-ray reflectivity, and neutron radiography. We show that the film-substrate adhesion and film purity are improved by increased substrate temperature and deposition rate. A deposition rate of 3.8 Å /s and substrate temperature of 400 C result in films with a density close to bulk values and good adhesion to film thickness above 3 lm. Boron-10 contents of almost 80 at. % are obtained in 6.3 m 2 of 1 lm thick 10 B 4 C thin films coated on Al-blades. Initial neutron absorption measurements agree with Monte Carlo simulations and show that the layer thickness, number of layers, neutron wavelength, and amount of impurities are determining factors. The study also shows the importance of having uniform layer thicknesses over large areas, which for a full-scale detector could be in total $1000 m

The Multi-Blade is a Boron-10-based gaseous detector introduced to face the challenge arising in neutron reflectometry at pulsed neutron sources. Neutron reflectometers are the most challenging instruments in terms of instantaneous counting rate and spatial resolution. This detector has been designed to cope with the requirements set for the reflectometers at the upcoming European Spallation Source (ESS) in Sweden. Based on previous results obtained at the Institut Laue-Langevin (ILL) in France, an improved demonstrator has been built at ESS and tested at the Budapest Neutron Centre (BNC) in Hungary and at the Source Testing Facility (STF) at the Lund University in Sweden. A detailed description of the detector and the results of the tests are discussed in this manuscript.

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The Multi-Blade is a Boron-10-based gaseous thermal neutron detector developed to face the challenge arising in neutron reflectometry at neutron sources. Neutron reflectometers are challenging instruments in terms of instantaneous counting rate and spatial resolution. This detector has been designed according to the requirements given by the reflectometers at the European Spallation Source (ESS) in Sweden. The Multi-Blade has been installed and tested on the CRISP reflectometer at the ISIS neutron and muon source in UK. The results on the detailed detector characterization are discussed in this manuscript.

The electronic structure and chemical bonding of wurtzite-GaN investigated by N 1s soft x-ray absorption spectroscopy and N K, Ga M 1 , and Ga M 2,3 emission spectroscopy is compared to that of pure Ga. The measurements are interpreted by calculated spectra using first-principles density-functional theory ͑DFT͒ including dipole transition matrix elements and additional on-site Coulomb interaction ͑WC-GGA+ U͒. The Ga 4p-N 2p and Ga 4s-N 2p hybridization and chemical bond regions are identified at the top of the valence band between −1.0 and −2.0 and further down between −5.5 and −6.5 eV, respectively. In addition, N 2s-N 2p-Ga 4s and N 2s-N 2p-Ga 3d hybridization regions occur at the bottom of the valence band between −13 and −15 eV, and between −17.0 and −18.0 eV, respectively. A bandlike satellite feature is also found around −10 eV in the Ga M 1 and Ga M 2,3 emission from GaN, but is absent in pure Ga and the calculated ground-state spectra. The difference between the identified spectroscopic features of GaN and Ga are discussed in relation to the various hybridization regions calculated within band-structure methods.

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The electronic structure of nanolaminate Ti 2 AlN and TiN thin films has been investigated by bulk-sensitive soft x-ray emission spectroscopy. The measured Ti L 2,3 , N K, Al L 1 , and Al L 2,3 emission spectra are compared with calculated spectra using ab initio density-functional theory including dipole transition-matrix elements. Three different types of bond regions are identified; a relatively weak Ti 3d-Al 3p bonding between −1 and −2 eV below the Fermi level, and Ti 3d-N 2p and Ti 3d-N 2s bondings which are deeper in energy observed at −4.8 eV and −15 eV below the Fermi level, respectively. A strongly modified spectral shape of 3s states of Al L 2,3 emission from Ti 2 AlN in comparison with pure Al metal is found, which reflects the Ti 3d-Al 3p hybridization observed in the Al L 1 emission. The differences between the electronic and crystal structures of Ti 2 AlN and TiN are discussed in relation to the intercalated Al layers of the former compound and the change of the materials properties in comparison with the isostructural carbides.