Effect of Sb deficiency on the thermoelectric properties of Zn4Sb3

We have investigated the effect of Sb-deficiency on the thermoelectric figure of merit (zT) of Zn4Sb3 prepared by solid state reaction route. At high temperatures, the Seebeck coefficient (S) and electrical conductivity ({\sigma}) increase with increase in Sb deficiency whereas the thermal conductivity (\k{appa}) decreases giving rise to an increase in the overall zT value. The observations suggest that creation of vacancies could be an effective route in improving the thermoelectric properties of Zn4Sb3 system. This coupled to nanostructuring strategy could lead to the ultimate maximum value of zT in this system for high temperature thermoelectric applications

Household savings and residential mobility in informal settlements

Strategies to help the one billion people worldwide who live in informal settlements have mainly focused on slum upgrading, sites and services programs, and tenure security. In contrast, there has been less attention on what enables slum dwellers to transition into the formal housingsector, which has the dual benefits of improving service access and escaping social stigma. In this paper the authors investigate residential mobility among slum dwellers in Bhopal, India. Their analysis shows that one in five households succeeds in getting out of a slum settlement, and a major determinant is the household's ability to save on a regular basis. Due to limited outreach of institutional housing finance, most slum dwellers rely solely on household savings for purchasing a house. These findings underscore the urgent need to improve savings instruments for slum dwellers and to downmarket housing finance to reach the poorest residents of rapidly growing cities in developing countries.Housing&Human Habitats,Urban Housing,Banks&Banking Reform,Urban Services to the Poor,Urban Services to the Poor

Growth, Characterization, Vortex Pinning and Vortex Flow Properties of Single Crystals of Iron Chalcogenide Superconductor FeCr0.02_{0.02}Se

We report the growth and characterization of single crystals of iron chalcogenide superconductor FeCr$_{0.02}$Se. There is an enhancement of the superconducting transition temperature (T$_{\rm c}$) as compared to the T$_{\rm c}$ of the single crystals of the parent compound Fe$_{1+x}$Se by about 25%. The superconducting parameters such as the critical fields, coherence length, penetration depth and the Ginzburg-Landau parameter have been estimated for these single crystals. Analysis of the critical current data suggests a fluctuation in electronic mean free path induced ($\delta l$) pinning mechanism in this material. Thermally activated transport across the superconducting transition in the presence of external magnetic fields suggests a crossover from a single vortex pinning regime at low fields to a collective flux creep regime at higher magnetic fields. The nature of charge carriers in the normal state estimated from the Hall effect and thermal transport measurements could provide crucial information on the mechanism of superconductivity in Fe-based materials.Comment: 2 additional figures, additional discussion on nature of charge carrier