mapping of chemical order in inorganic compounds
DESCRIPTION
Presentations of some of the possibilities of observing cation and anion order in perosvkite based structures in order to solve their structure or to solve other questions, when they could not be solved by bulk diffraction techniques. The examples include a (Pb,Bi)FeO3-d compound, a solid oxide fuel cell compound Sr(Nb,Co,Fe)O3-d and several brownmillerite related compounds, as well as a "relaxor ferromagnetic". This was an invited lecture given at the Spring meeting of the British Crystallographic Association in 2014.TRANSCRIPT
Mapping of chemical order in inorganic compounds
Maria Batuk, Dmitry Batuk, Artem M. Abakumov, Joke
Hadermann
2
B-cation: transition metal
(Fe3+, Ti4+, Zr4+, Nb5+, …)
Perovskite structure Cubic structure
Space group Pm3m
Unit cell parameter
ap 3.8 – 4.2Å
ABO3
A-cation: alkali, alkali-earth
(Ba2+, Sr2+), rare-earth metals,
Bi3+, Pb2+
3
SrCo0.8Fe0.2O3-δ highest flux among La1-xSrxCo1-yFeyO3-δ perovskites
Brownmillerite structure at RT
+ Nb
Reported disordered perovskite at RT
Problem:
14
The structure of Pb0.65Bi0.31Fe1.04O2.68
Refined structure
Annular Bright Field (ABF)
STEM I ~ Z1/3
High Angle Annular Dark Field (HAADF)
STEM I ~ Z1.6-1.9
15
15
a ≈ 3.92Å ≈ ap, c ≈ 51.52Å ≈ 13ap octahedra FeTi2: 0.63Fe + 0.37Ti pyramids FeTi1: 0.87Fe + 0.13Ti
Pb6BiFe3TiO13Cl2
Cl
PbBiO2 Cl
Perovskite block
Rietveld refinement:
19
La3Sb2NiO9
Peter Battle, Oxford University
La0.25Sr0.75MnO2.38, La0.17Sr0.83MnO2.36 and SrMnO2.22
Edward Dixon and Michael Hayward, Oxford University
Sr2Al0.78Mn1.22O5.2
Anna S. Kalyushnaya, Marina G. Rozova, Evgeny V. Antipov, Moscow State University
SrCo0.7Fe0.2Nb0.1O2.72
Olga Yu. Podyacheva, Boreskov Institute of Catalysis
EELS on SrCo0.7Fe0.2Nb0.1O2.72
Stuart Turner, EMAT
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These slides can also be found on Slideshare/johader
'Layered oxygen vacancy ordering in Nb-doped SrCo1-xFexO3-delta perovskite' S. Van Rompaey, W. Dachraoui, S. Turner, O.Y. Podyacheva, H.Y. Tan, J. Verbeeck, A.M. Abakumov, J. Hadermann
Zeitschrift fur Kristallografie, 228 (2013) 28-34 'Synthesis,crystal structure and magnetic properties of the Sr2Al0.78Mn1.22O5.2 anion-deficient layered perovskite ' Hans D’Hondt, Joke Hadermann, Artem M.Abakumov, Anna S.Kalyuzhnaya, Marina G. Rozova, Alexander A. Tsirlin, Ramesh Nath, Haiyan Tan, Jo Verbeeck, Evgeny V. Antipov, Gustaaf Van Tendeloo
Journal of Solid State Chemistry 182, 356–363 (2009). 'Structures and Magnetism of La1−xSrxMnO3−(0.5+x)/2 (0.67 ≤ x ≤ 1) Phases ' E. Dixon, J. Hadermann, M. Hayward
Chem. Mater. 2012, 24, 1486−1495 'Pb5Fe3TiO11Cl: a rare example of Ti(IV) in a square pyramidal oxygen coordination' Maria Batuk1,*, Dmitry Batuk1, Artem M. Abakumov1,2, Joke Hadermann1
Accepted by Journal of Solid State Chemistry Abakumov, A. M.; Batuk, D.; Hadermann, J.; Rozova, M. G.; Sheptyakov, D. V.; Tsirlin, A. A.; Niermann, D.; Waschkowski, F.; Hemberger, J.; Van Tendeloo, G.; Antipov, E. V. Antiferroelectric (Pb,Bi)1− xFe1+ xO3− y Perovskites Modulated by Crystallographic Shear Planes. Chemistry of Materials 23, 255–265 (2011).