Neutron diffraction studies and the magnetism of an ordered perovskite: Ba(2)CoTeO(6).
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.
Ivanov
S A
SA
Department of Inorganic Materials, Karpov' Institute of Physical Chemistry, Vorontsovo pole, 10 105064, Moscow K-64, Russia. ivan@cc.nifhi.ac.ru
Nordblad
P
P
Mathieu
R
R
Tellgren
R
R
Ritter
C
C