Abstract
The synthesis and characterization of six members of the ordered quintuple copper titanium perovskite series LnBaCaCuTiO are reported. Structural characterization, carried out by a combination of powder X-ray and powder neutron diffraction and EXAFS, shows full ordering of the cations for Ln = Sm, Eu, Gd in the tetragonal space group P4/mmm with the B type cations stacked in the order Cu-Ti-Ti-Ti-Cu. For Ln = Nd partial disorder on both the A and B cation sublattices occurs and oxygen is incorporated between the CuO layers. In LaBaCaCuTiO there is full disordering on both the A and B cation lattices leading to a simple cubic unit cell. When Ln = Tb and Dy, the symmetry of the structure is reduced to an orthorhombic cell, though the B cation stacking is maintained. In all materials the TiO octahedra are distorted. The in-plane Cu-O distances are similar to those found in high-temperature superconductors and are significantly shorter than those found in the corresponding quadruple copper titanium lanthanide perovskites.
Original language | English |
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Pages (from-to) | 1547-1553 |
Journal | Chemistry of Materials |
Volume | 9 |
Issue number | 7 |
DOIs | |
Publication status | Published - 1997 |