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Lecture I. Zvereva


24 januari 2006 FWN-Building 5118.0153, Nijenborgh 4, 9747 AG, Groningen
Speaker:Prof. I. Zvereva
Affiliation:Saint Petersburg State University, Department of Chemistry, Russia
Title:Mechanism of formation of perovskite-type layer structures
Date:Tue Jan 24, 2006
Location:FWN-Building 5118.0153
Host:T.T.M. Palstra
Telephone:+31 50 363 4419


A brief review of structural aspects of the process of formation and the stability of Ruddlesden-Popper phases which exhibit the layered-type structure will be presented. Ruddlesden-Popper phases exhibit a wealth of physical and chemical properties and could be converted to other groups of perovskite-like structures. The object of the investigation is the intergrowth of ABO3 perovskite (P) and AO rock salt (RS) type slabs. The experimental basis for these considerations is data on aluminates Ln2SrAl2O7, ferrites Ln2SrFe2O7, manganites LnSr2Mn2O7 and titanates NaLnTiO4. As additional aspects of the problem of phase stability, information on ordering phenomena which create boundaries for the existence of the layered type of structure will be considered. A non-statistical distribution of the non-isovalent atoms Ln and Sr over two non-equivalent sites (the AO12 one in the P layers and the AO9 one in the RS slabs) progressively develops across the lanthanide series and results in some ordering phenomena. Phase diagrams in pseudobinary systems in which one can find Ln2SrM2O7 possessing the P2/RS type of intergrowth are discussed in connection with transformations in the cationic coordination during the process of formation.
Laatst gewijzigd:22 oktober 2012 14:30