Title 2√2 $a_{p}$ x 2√ $a_{p}$ phase in superconducting ceramics Author Krekels, T. Kaesche, S. Van Tendeloo, G. Faculty/Department Faculty of Sciences. Physics Publication type article Publication 1995 Amsterdam , 1995 Subject Physics Source (journal) Physica: C: superconductivity. - Amsterdam Volume/pages 248(1995) :3/4 , p. 317-327 ISSN 0921-4534 ISI A1995RJ45000012 Carrier E Target language English (eng) Full text (Publishers DOI) Affiliation University of Antwerp Abstract By means of electron diffraction the 2 root 2 a(p) x 2 root 2 a(p) phase, well-known in YBa2Cu3O7-delta was observed in two other perovskite-based materials (Y0.75Ce0.25)(2)(Sr0.85Y0.15)(2)AlCU2O9 and Bi1.8Pb0.4Sr2Ca2Cu3O10+x. Highly correlated ordering is observed in the ab-plane, the correlation along the c-direction being weak. The plane group of the superstructure symmetry elements was determined on the basis of observed reflection conditions in diffraction patterns. Our results unambiguously rule out oxygen ordering as a possible origin of the superstructure. Experimental evidence points out that the superstructure is associated with the CuO2 layers, that are the only structural elements common to the three compounds studied. A model is proposed where the CuO2 sheet is displacively modulated. Experimental evidence suggests a correlation between adjacent CuO2 sheets. Comparison of simulated and experimental [001] zone diffraction patterns strongly supports our model. E-info https://repository.uantwerpen.be/docman/iruaauth/12eac1/caf3584.pdf http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:A1995RJ45000012&DestLinkType=RelatedRecords&DestApp=ALL_WOS&UsrCustomerID=ef845e08c439e550330acc77c7d2d848 http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:A1995RJ45000012&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=ef845e08c439e550330acc77c7d2d848 http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:A1995RJ45000012&DestLinkType=CitingArticles&DestApp=ALL_WOS&UsrCustomerID=ef845e08c439e550330acc77c7d2d848 Handle