Post on 10-May-2015
description
A
Lone pair cations like Bi3+ or Pb2+ are comfortable in an asymmetric coordination environment...
...and we use this to create interfaces to get new types of structures.
One type is the focus of this presentation:
Shift one part of the structure relative to the
other.
This is called a shear plane.
This gives us perovskite based crystallographic shear plane structures.
Shear plane structures were known in other compounds , but were believed to be impossible in perovskites.
(101) CS planes
(h0l) CS planes
We can vary orientation...
Pb1-xSrxFeO2.5+δ
...by playing with the ratio lone pair to non lone pair cations
higher Pb:Sr
lower Pb:Sr
Pb2+:Bi3+=7:0.5
We can vary the distance between the interfaces...
Pb2+:Bi3+=7:3
Pb2+:Bi3+= 7:5 Pb2+:Bi3+= 7:8
HAADF-STEM
images
Pb1-xBixFeO2.5+x/2
...by playing with the oxygen content.
n=4
n=6 n=5
This also gives a new homologous series.
AnBnO3n-2
27
Ruddlesden-Popper An+1BnO3n+1
Dion-Jacobson AnBnO3n+1
Aurivillius Bi2An-1BnO3n+3
AnBnO3n-2
AO―
AO― A―
A―
A― O2―
ABO―
ABO―
If you compare to other homologous series...
27
Ruddlesden-Popper An+1BnO3n+1
Dion-Jacobson AnBnO3n+1
Aurivillius Bi2An-1BnO3n+3
AnBnO3n-2
AO―
AO― A―
A―
A― O2―
ABO―
ABO―
...the others have electrically and magnetically inactive interfaces between the perovskite blocks...
27
Ruddlesden-Popper An+1BnO3n+1
Dion-Jacobson AnBnO3n+1
Aurivillius Bi2An-1BnO3n+3
AnBnO3n-2
AO―
AO― A―
A―
A― O2―
ABO―
ABO―
...in the new series the perovskite blocks still interact...
...this leads to a magnetically frustrated structure!
G-type
The perovskite block are antiferromagnetically ordered within...
J2
J1
Fe
O Fe
Fe
O J1
...but when you stack two blocks, some spins at the interface cannot satisfy all exchange interactions.
G-type
J2
J1
Fe
O Fe
Fe
O J1
Goodenough-Kanamoori rules say...
J2
J1
Fe
O Fe
Fe
O J1
Goodenough-Kanamoori rules say...
AFM
J2
J1
Fe
O Fe
Fe
O J1
Goodenough-Kanamoori rules say...
FM FM
AFM
J2
J1
Fe
O Fe
Fe
O J1
Goodenough-Kanamoori rules say...
FM FM
AFM
...but that is impossible.
Just to close off, we can get some funny interfaces too:
HAADF-STEM image
For all details, on which compounds, how and why, you'll have to look up the papers:
Dmitry Batuk, Maria Batuk, Artem M. Abakumov, Alexander A. Tsirlin, Catherine McCammon, Leonid Dubrovinsky, Joke Hadermann "Effect of lone electron pair cations on the orientation of crystallographic shear planes in anion-deficient perovskites" Submitted to Inorganic Chemistry (2013) M. Batuk, O. A. Tyablikov, A. A. Tsirlin, S. M. Kazakov, M. G. Rozova, K. V. Pokholok, D. S. Filimonov, E. V. Antipov, A. M. Abakumov, J. Hadermann. “Structure and magnetic properties of a new anion-deficient perovskite Pb2Ba2BiFe4ScO13 with crystallographic shear structure” Materials Research Bulletin 48 (2013) 3459-3465 A. M. Abakumov, M. Batuk, A. A. Tsirlin, O. A. Tyablikov, D. V. Sheptyakov, D. S. Filimonov, K. V. Pokholok, V. S. Zhidal, M. G. Rozova, E. V. Antipov, J. Hadermann, G. Van Tendeloo. “Structural and magnetic phase transitions in Pb2Ba2BiFe5O13 and Pb1.5Ba2.5Bi2Fe6O16: 5th and 6th members of the AnBnO3n-2 perovskite-based homologous series” Inorganic Chemistry 52 (2013) 7834-7843 Turner, S.; Egoavil, R.; Batuk, M.; Abakumov, A. A.; Hadermann, J.; Verbeeck, J.; Van Tendeloo, G. "Site-specific mapping of transition metal oxygen coordination in complex oxides. " Applied Physics Letters 101, 241910 (2012).
continued on next slide
Korneychik, O. E.; Batuk, M.; Abakumov, A. M.; Hadermann, J.; Rozova, M. G.; Sheptyakov, D. V.; Pokholok, K. V.; Filimonov, D. S.; Antipov, E. V. "Pb2.85Ba2.15Fe4SnO13: A new member of the AnBnO3n−2 anion-deficient perovskite-based homologous series. " Journal of Solid State Chemistry 184, 3150–3157 (2011). Batuk, D.; Hadermann, J.; Abakumov, A.; Vranken, T.; Hardy, A.; Van Bael, M.; Van Tendeloo, G. "Layered perovskite-like Pb2Fe2O5 structure as a parent matrix for the nucleation and growth of crystallographic shear planes." Inorganic chemistry 50, 4978–86 (2011). 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). Hadermann, J.; Abakumov, A. M.; Perkisas, T.; D’Hondt, H.; Tan, H.; Verbeeck, J.; Filonenko, V. P.; Antipov, E. V.; Van Tendeloo, G. "New perovskite based manganite Pb2Mn2O5", Journal of Solid State Chemistry 183, 2190–2195 (2010). Abakumov, A. M.; Hadermann, J.; Batuk, M.; D’Hondt, H.; Tyablikov, O. A.; Rozova, M. G.; Pokholok, K. V; Filimonov, D. S.; Sheptyakov, D. V; Tsirlin, A. A.; Niermann, D.; Hemberger, J.; Van Tendeloo, G.; Antipov, E. V "Slicing the perovskite structure with crystallographic shear planes: the AnBnO3n-2 homologous series." Inorganic chemistry 49, 9508–16 (2010). Van Tendeloo, G.; Hadermann, J.; Abakumov, A. M.; Antipov, E. V. "Advanced electron microscopy and its possibilities to solve complex structures: application to transition metal oxides. " Journal of Materials Chemistry 19, 2660 (2009). I.V. Nikolaev, H. D'Hondt, A.M. Abakumov, J. Hadermann, A.M. Balagurov, I.A. Bobrikov, D.V. Sheptyakov, V.Yu. Pomjakushin, K.V. Pokholok, D.S. Filimonov, G. Van Tendeloo, E.V. Antipov, "Crystal structure, phase transition, and magnetic ordering in perovskitelike Pb2-xBaxFe2O5 solid solutions", Phys. Rev. B, 78:2 (2008) p. 024426, 1-12 Abakumov, A.M., Hadermann, J., Van Tendeloo, G., Antipov, E.V., "Chemistry and structure of anion deficient perovskites with translational interfaces", Journal of the American Ceramic Society 91,6 (2008) 1807-1813 Hadermann, J., Abakumov, A.M., Nikolaev, I.V., Antipov, E.V., Van Tendeloo, G., "Local structure of perovskite-based "Pb2Fe2O5" ", Solid State Sciences 10, 4 (2008) 382-389 Abakumov, A.M., Hadermann, J., Bals, S., Nikolaev, I.V., Antipov, E.V., Van Tendeloo, G. "Crystallographic Shear Structures as a Route to Anion-Deficient Perovskites", Angewandte Chemie International Edition,Volume 45, Issue 40 (2006) 6697-6700