Abstract to be announced

The slow muons technique provides a quantitative approach to characterize the effect of various cover layers on the passivation of bulk defects near the p-n junction of solar cells [1]. Several cover layers on top of the chalcopyrite Cu(In,Ga)Se2 (CIGS) semiconductor absorber were investigated in this work, namely CdS, ZnSnO, Al2O3 and SiO2. The figure shows the depth profile of a measurement on a CdS/CIGS sample. The diamagnetic fraction is used as an indication of the perturbation of the lattice at the site of the muon. The lower part of the figure shows the model depth profile obtained after deconvolution of the experimental data with the range distribution function. The dip in the diamagnetic fraction near the interface indicates that the lattice is more perturbed in this near-interface region than further inward in the sample. We find that CdS provides the best defect passivation; the oxide materials are less effective.

In this study, electrospinning has been employed to produce micro to nano scale fibres of whey protein in order to investigate their potential for use in the food industry. Initially, spinning of pure whey protein proved challenging; so in order to facilitate the spinning of freshly prepared aqueous solutions, small amounts of polyethylene oxide (as low as 1% w/w in solution) were incorporated in the spinning solutions. The electrospun composite polyethylene-oxide/whey fibres exhibited diameters in the region of 100 to 400 nm, showing the potential to build fibre bundles from this size up. Time-dependent examinations of pure whey protein aqueous solutions were conducted using rheometery and small angle neutron scattering techniques, with the results showing a substantial change in the solution properties with time and stirring; and allowing the production of fibres, albeit with large diameters, without the need for an additive. We develop a method of analysis of the data involving a model of the protein and how the various interactions impact of the data. The spinability is related to the potential of the whey protein composites to form aggregate structures, either through hydration and interaction with neighbouring proteins, or through interaction with the polyethylene oxide.

In this work, a comprehensive muon spin spectroscopy (µSR) of TbMnO3 single crystal is reported, following previously observed anomalies on the magnetization, lattice parameters and phonon energies in the 5 to 300 K range. First-principles calculations based on density-functional theory with on-site Coulomb interactions were also carried out to determine all possible equilibrium sites of the muon defects, µ+. For all distinct muon sites, the corresponding hyperfine parameters were also obtained. The Knight shift versus temperature shows a S-shaped curve at around 200 K, mirroring a similar temperature behavior as the magnetic susceptibility. However, the Knight shift perfectly scales by the magnetic susceptibility, which evidences magnetic changes, underlid by the same microscopic mechanism. By a comparative study of the reported experimental results and previously published ones, we assign the microscopic mechanisms to lattice distortions. This interpretation highlights a rather unusual magnetoelastic coupling.

Abstract to be announced

Abstract to be announced