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Recurrent Intergrowths in the Topotactic Reduction Process of LaBaCuCoO 5.2
Author(s) -
RuizGonzález Luisa,
Boulahya Khalid,
Parras Marina,
Alonso José,
GonzálezCalbet José M.
Publication year - 2002
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/1521-3765(20021216)8:24<5694::aid-chem5694>3.0.co;2-#
Subject(s) - superlattice , perovskite (structure) , crystallography , reduction (mathematics) , oxide , materials science , layer (electronics) , oxygen , process (computing) , chemistry , nanotechnology , optoelectronics , mathematics , computer science , metallurgy , geometry , operating system , organic chemistry
A new perovskite‐related oxide with the LaBaCuCoO 5.2 composition has been stabilised. Its structure can be described as formed by the recurrent intergrowth of two alternating blocks of YBaCuFeO 5 (2a c , i.e., two‐fold perovskite superlattice) and YBa 2 Fe 3 O 8 (3a c ) structural types. From the starting material LaBaCuCoO 5.2‐ δ ( δ =0), the rigorous control of the oxygen content has allowed the stabilisation of three new fivefold perovskite‐related superstructures with the compositions δ =0.4, 0.8 and 1.1, which can also be described as recurrent intergrowths of two blocks showing 2 a c and 3 a c periodicity. The reduction process takes place through the 3 a c periodic blocks, when 0< δ <0.8. Further oxygen decrease seems to involve the 2 a c periodic blocks made up of pyramidal layers, giving rise to infinite layer units. The stability limit for these fivefold superstructures is δ =1.1. In agreement with this the as‐synthesised materials constitute an example of topotactic reaction, since their basic structure is kept through the reduction process.