Unexpected effect of Ru-substitution in lightly doped manganites

In this Communication we report about the unexpected effect of ruthenium doping in sodium ligthly-doped manganites. This effect seems to be in contrast with the usual model applied to describe the effect of this magnetic ion into the manganite structure. We propose a possible compensation mechanism which seems also able to describe other peculiar features encountered in these materials.Comment: 3 pages, 2 Figures to appear in ChemCom

Design of a bioinspired ray robot with flexible fins

This paper presents the design and construction of a biomimetic swimming robot inspired by the locomotion of rays. These fishes move by flapping their pectoral fins and creating a wave that moves in the opposite direction to the direction of motion, pushing the water back and giving the fish a propulsive force due to momentum conservation. The robot's fins are molded from silicone rubber and moved by a servo motor that drives a mechanism inside the leading edge of each fin. The traveling wave, mimicking the movement of the fin, is passively generated by the flexibility of the rubber itself. The robot is also equipped with a tail that acts as a rudder, helpful in performing maneuvers. The rigid central body of the robot is the housing for motors, electronics, and batteries

Lattice strain effects on doping, hydration and proton transport in scheelite-type electrolytes for solid oxide fuel cells

Lattice strain is considered a promising approach to modulate the structural and functional properties of oxide materials. In this study we investigate the effect of lattice strain on doping, hydration and proton transport for the family of scheelite-type proton conductors using both atomistic and DFT computational methods. The results suggest that tensile strain improves the dopant solubility and proton uptake of the material. The anisotropic proton pathways change from being within the a-b plane to being in the a-c plane. However, the predicted reduction in the migration barrier suggests that improvements in ionic conductivity due to lattice strain effects will be limited, in contrast with the work on oxide ion conduction. Such results are rationalized in terms of structural changes and differences in migration steps between oxide ions and protonic species.</p

Feeling the strain:enhancing ionic transport in olivine phosphate cathodes for Li- and Na-ion batteries through strain effects

Olivine-type phosphates LiFePO4 and NaFePO4 are among the most widely studied cathode materials for rechargeable batteries. Here we show that tensile strain applied perpendicularly to the alkali-ion migration channels will improve their intercalation properties.</p

High Temperature Neutron Diffraction Study of the La1.4Sr1.6mn2o7 Bilayered Manganite

In this paper we present the results of a high temperature (300 K<T<800 K) neutron powder diffraction study of the La1.4Sr1.6Mn2O7 bilayered manganite. An unusual trend of the /Mn-Oequatorial parameter was found: it first decreases up to 500 K and then increases up to the highest T measured. At the same time, a significant shortening of the apical Mn-O(2) bond is observed in the range where the J-T distortion is reduced. The overall data gained by this study may suggest a shift of electronic density from axial to planar eg orbitals with T. This trend is explained considering of the presence of short range magnetic interaction well above TC.Comment: 18 pages, 6 figure

Lattice strain effects on doping, hydration and proton transport in scheelite-type electrolytes for solid oxide fuel cells

Tensile lattice strain enhances Ca dopant limit and proton incorporation in scheelite-type proton conductors, modifying the preferential conduction pathways.</p

High Pressure X-ray Diffraction Study of MgMn2O4 Tetragonal Spinel

The phase stability of the MgMn2O4 spinel has been studied by means of high-pressure X-ray diffraction for pressures up to 30 GPa. Two samples with different inversion degrees have been considered. Both spinels undergo a phase transition towards an orthorhombic structure (CaMn2O4-type). For the more inverted sample the transition pressure is at least 1 GPa lower with respect to that of the less inverted spinel. Also the volume contraction, relative compressibility and density trends are different for the two samples. These variations have been explained according to differences in the cation distribution. and electronic properties of the samples.Comment: 12 pages; 4 Figures presented at the SRMS-