12 research outputs found
Is Tl2Ni3S2 a mixed valent compound? Crystal and electronic structure investigations
Jim Lehrer on a screen set up on Squarehttps://egrove.olemiss.edu/debate_photo/1301/thumbnail.jp
The magnetoelectric effect across scales
Magnetoelectric coupling can arise in intrinsic multiferroics as well as composites. We will outline how for intrinsic BiFeO3 nanoparticles yield different magnetoelectric properties at room temperature than larger grains or bulk material. Magnetoelectric nanoscale composites of BaTiO3 and CoFe2O4 display rather poor magnetoelectric coupling macroscopically. Their micron scale counterparts on the other hand yield nice macroscopic response. The mechanical, electrical, and magnetic effects are analyzed using techniques including Mössbauer spectroscopy, magnetic force microscopy, piezoforce microscopy, and macroscopic techniques. It will be shown that microscopic coupling is strong also for (partly) conducting magnetic inclusions and nanosystems while macroscopic properties are highly dependent on good insulation of the samples. Experimental asymmetries in determining the magnetoelectric coupling coefficient are discussed. Support via FP7 Marie Curie Initial Training Network *Nanomotion* (grant nâ 290158) & Forschergruppe 1509 are acknowledged
Hysteresis-Free Lead-Free Double-Perovskite Solar Cells by Interface Engineering
Hybrid
perovskite solar cells have been creating considerable excitement
in the photovoltaic community. However, they still rely on toxic elements,
which impose severe limits on their commercialization. Lead-free double
hybrid perovskites in the form of Cs<sub>2</sub>AgBiBr<sub>6</sub> have been shown to be a promising nontoxic and highly stable alternative.
Nevertheless, device development is still in its infancy, and performance
is affected by severe hysteresis. Here we realize for the first time
hysteresis-free mesoporous double-perovskite solar cells with no <i>s</i>-shape in the device characteristic and increased device
open-circuit voltage. This has been realized by fine-tuning the material
deposition parameters, enabling the growth of a highly uniform and
compact Cs<sub>2</sub>AgBiBr<sub>6</sub>, and by engineering the device
interfaces by screening different molecular and polymeric hole-transporting
materials. Our work represents a crucial step forward in lead-free
double perovskites with significant potential for closing the gap
for their market uptake
The social consequences of the denied access to housing for refugees in urban settings: the case of Turin, Italy
The paper focuses on the access to housing of refugees, considering it an essential step on the integration path and a precondition for the full enjoyment of social and civil rights as well as social services. In Western countries, refugees mostly live in urban settings and local authorities' actions and decisions play a relevant role in shaping opportunities and obstacles for social inclusion. Lack of, or deficiencies in housing policies can result in challenging situations, jeopardising this path. The paper investigates the obstacles local authorities create through both informal practices and administrative provisions. The analysis highlights a gap between the national legal framework and its local implementation that creates major disruptions in the integration path. The paper takes the city of Turin (Italy) as a case study. A multi-method study was carried out to investigate these issues in the period between November 2007 and July 2013. In the case of Turin, within a scenario characterised by a huge absence of systematic policies supporting refugees' access to housing, many refugees have opted for squatting. While underlining refugees' agency, these experiences appear unable to properly tackle their housing needs and to achieve the objectives of social recognition and public solidarity