title: Neutron diffraction studies and the magnetism of an ordered perovskite: Ba(2)CoTeO(6).
abstract: The complex perovskite Ba(2)CoTeO(6) (BCTO) has been synthesised, and the crystal structure and magnetic properties have been investigated using a combination of X-ray and neutron powder diffraction, electron microscopy and dielectric, calorimetric and magnetic measurements. It is shown that at room temperature this compound adopts the 6L-trigonal perovskite structure, space group P3[combining macron]m (s.g. 164) (a = 5.7996(1) A, c = 14.2658(3) A). The structure comprises dimers of face-sharing octahedra as well as octahedra which share only vertices with their neighbours. Dielectric measurements indicate a diffuse transition of antiferroelectric nature near 280 K. A long-range antiferromagnetically ordered state has been identified from neutron diffraction and magnetic studies. The magnetic diffraction peaks were registered below the magnetic transition at about 15 K and a possible model for the magnetic structure is proposed. The structural and magnetic features of this compound are discussed and compared with those of other Co-based quaternary oxides adopting the perovskite structure.
authors.affiliation: Department of Inorganic Materials, Karpov' Institute of Physical Chemistry, Vorontsovo pole, 10 105064, Moscow K-64, Russia. ivan@cc.nifhi.ac.ru
authors.forename: S A
authors.initials: SA
authors.lastname: Ivanov
authors.forename: P
authors.initials: P
authors.lastname: Nordblad
authors.forename: R
authors.initials: R
authors.lastname: Mathieu
authors.forename: R
authors.initials: R
authors.lastname: Tellgren
authors.forename: C
authors.initials: C
authors.lastname: Ritter