X-ray powder reference patterns for magnetoplumbite-like compounds, (BaxSr1−x)Ti6Co6O19(x= 0.2, 0.4, 0.6, 0.8)

Abstract

X-ray reference powder patterns and crystal structures have been determined for a series of titanium- and cobalt-containing layered alkaline-earth compounds with nominal formula (BaxSr1−x)Ti6Co6O19(x= 0.2, 0.4, 0.6, 0.8). Structural isomorphism of the title compounds with the hexagonal ferrite BaFe12O19and magnetoplumbite (PbFe12O19), was confirmed. The (BaxSr1−x)Ti6Co6O19series crystallize in the space group ofP63/mmc(No. 194) andZ= 2. The lattice parameters range froma= 5.90729(6) Å,c= 23.2378(3) Å, andV= 702.27(2) Å3forx= 0.2 toa= 5.914 93(9),c= 23.3391(5) Å, andV= 707.15(2) Å3withx= 0.8. The structure consists of alternating spinel S-block and R-blocks. The tetrahedral sites within the spinel S-blocks are occupied with only Co2+, while Ti4+is mainly located in the octahedral sites of the spinel S-blocks and in the face-sharing octahedral site of the R-blocks. A bipyramidal mixed Co/Ti site was confirmed in the R-block of the structure. Powder X-ray diffraction patterns of this series of compounds have been submitted to be included in the Powder Diffraction File.