SENJU: a new time-of-flight single-crystal neutron diffractometer at J-PARC.

SENJU is a new single-crystal time-of-flight neutron diffractometer installed at BL18 at the Materials and Life Science Experimental Facility of the Japan Accelerator Research Complex (J-PARC). The diffractometer was designed for precise crystal and magnetic structure analyses under multiple extreme sample environments such as low temperature, high pressure and high magnetic field, and for diffraction measurements of small single crystals down to 0.1 mm in volume.

Redetermination of Nd2Ti2O7: a non-centrosymmetric structure with perovskite-type slabs.

Single crystals of dineodymium(III) dititanium(IV) hepta-oxide, Nd2Ti2O7, were synthesized by the flux method and found to belong to the family of compounds with perovskite-type structural motifs. The asymmetric unit contains four Nd, four Ti and 14 O-atom sites. The perovskite-type slabs are stacked parallel to (010) with a thickness corresponding to four corner-sharing TiO6 octa-hedra.

Determination of the local structure of a cage with an oxygen ion in Ca12Al14O33.

The crystal structure of mayenite (12CaO·7Al(2)O(3)) has been investigated by single-crystal synchrotron diffraction with high resolution and accuracy, using a four-circle diffractometer equipped with an avalanche photodiode detector (APD) detector installed at PF14A in Tsukuba, Japan. Analysis revealed random displacements of ions by the electrostatic force of the O(2-) ion (O3) clathrated in two out of 12 cages. O3 ions are located at general positions close to the \bar 4 site at the centre of each cage.

A general expression of the polarization factor for multi-diffraction processes.

A general expression of the polarization factor of multi-diffracted beams is formulated. By assigning the diffracted beam direction of each diffraction process as the y axis of a Cartesian coordinate system, the polarization factor of multi-diffraction processes can be easily calculated for polarized and unpolarized beams without being limited by the number of diffraction processes. The method can be applied to processes with more than three scattering events such as multiple diffraction and extinction.

(Ca(x)Nd(11-x))Ru(4)O(24) (x = 4.175).

Single crystals of the title compound, calcium neodymium ruthenate, (Ca(x)Nd(11-x))Ru(4)O(24) (x = 4.175), have been grown by the flux method. The structure consists of two crystallographically independent RuO(6) octa-hedra, which are isolated from each other and embedded in a matrix composed of the Ca and Nd atoms.

Apatite-type SrPr(4)(SiO(4))(3)O.

Single crystals of the title compound, strontium tetra-praseo-dymium tris-(silicate) oxide, SrPr(4)(SiO(4))(3)O, have been grown by the self-flux method using SrCl(2). The structure is isotypic with the apatite supergroup family having the generic formula (IX)M1(2) (VII)M2(3)((IV)TO(4))(3)X, where M = alkaline earth and rare earth metals, T = Si and X = O. The M1 site (3.

Filled skutterudite structure of europium ruthenium polyphosphide, EuRu(4)P(12).

The crystal structure of EuRu(4)P(12) is isotypic with filled skutterudite structures of rare earth transition metal poly-phosphides: RFe(4)P(12) (R = Ce, Pr, Nd, Sm and Eu), RRu(4)P(12) (R = La, Ce, Pr and Nd) and ROs(4)P(12) (R = La, Ce, Pr and Nd). The Ru cation is coordinated by six P anions in a distorted octa-hedral manner. The partially occupied Eu position (site occupancy 0.

Tripraseodymium penta-iron(III) dodeca-oxide, Pr(3)Fe(5)O(12): a synchrotron radiation study.

The title compound, penta-iron tripraseodymium dodeca-oxide (PrIG), has an iron garnet structure. There are two Fe site symmetries. One of the Fe atoms is coordinated by six O atoms, forming a slightly distorted octa-hedron, and has site symmetry.

Trineodymium(III) penta-iron(III) dodeca-oxide, Nd(3)Fe(5)O(12).

The title compound, Nd(3)Fe(5)O(12) (NdIG), has an iron garnet structure. One of the Fe atoms is coordinated by six O atoms in a slightly distorted octa-hedral geometry and has site symmetry. The other Fe atom is coordinated by four O atoms in a slightly distorted tetra-hedral geometry and has site symmetry.