POWGEN: rebuild of a third-generation powder diffractometer at the Spallation Neutron Source.

The neutron powder diffractometer POWGEN at the Spallation Neutron Source has recently (2017-2018) undergone an upgrade which resulted in an increased detector complement along with a full overhaul of the structural design of the instrument. The current instrument has a solid angular coverage of 1.2 steradians and maintains the original third-generation concept, providing a single-histogram data set over a wide -spacing range and high resolution to access large unit cells, detailed structural refinements and / measurements.

Pb2MnTeO6 Double Perovskite: An Antipolar Anti-ferromagnet.

Pb2MnTeO6, a new double perovskite, was synthesized. Its crystal structure was determined by synchrotron X-ray and powder neutron diffraction. Pb2MnTeO6 is monoclinic (I2/m) at room temperature with a regular arrangement of all the cations in their polyhedra.

Magnetic-structure-stabilized polarization in an above-room-temperature ferrimagnet.

Above-room-temperature polar magnets are of interest due to their practical applications in spintronics. Here we present a strategy to design high-temperature polar magnetic oxides in the corundum-derived A2BB'O6 family, exemplified by the non-centrosymmetric (R3) Ni3TeO6-type Mn(2+)2Fe(3+)Mo(5+)O6, which shows strong ferrimagnetic ordering with TC = 337 K and demonstrates structural polarization without any ions with (n-1)d(10)ns(0), d(0), or stereoactive lone-pair electrons. Density functional theory calculations confirm the experimental results and suggest that the energy of the magnetically ordered structure, based on the Ni3TeO6 prototype, is significantly lower than that of any related structure, and accounts for the spontaneous polarization (68 μC cm(-2)) and non-centrosymmetry confirmed directly by second harmonic generation.

Unveiling structure-property relationships in Sr2Fe(1.5)Mo(0.5)O(6-δ), an electrode material for symmetric solid oxide fuel cells.

We characterize experimentally and theoretically the promising new solid oxide fuel cell electrode material Sr(2)Fe(1.5)Mo(0.5)O(6-δ) (SFMO).