Ferroelectricity and antiferroelectricity in tellurium containing compounds with perovskite structure

Neutron diffraction studies and the magnetism of an ordered perovskite: Ba2CoTeO6

“…Covalency implies directional bonding that will reduce the Coulomb repulsion between adjacent metal atoms. It is well-known [15,30,31] that there are only three structural degrees of freedom, which may be responsible for lattice distortion in complex perovskites: a) cation shifts, b) distortions of the oxygen polyhedra coordinating the cations in the A and B-sublattices and c) tilting of the oxygen octahedra. If one takes into account the values of the polyhedra distortions (see Table 4), the ferroic properties of BCTO may be connected with the Co(2) and Ba(3)-sublattices, which have significant values of the off-center cation displacements from their polyhedral centers.…”

“…BCTO was initially synthesised and investigated in the mid sixties [24,25] and then forgotten for a number of years. However, the compound experienced a regained interest [26][27][28][29][30][31] from the prospect of finding perovskite oxides with high Curie temperature. It was then also found, that an antiferroelectric phase transition, accompanied by anomalous dielectric properties occurs in BCTO close to room temperature [31].…”

“…However, the compound experienced a regained interest [26][27][28][29][30][31] from the prospect of finding perovskite oxides with high Curie temperature. It was then also found, that an antiferroelectric phase transition, accompanied by anomalous dielectric properties occurs in BCTO close to room temperature [31]. There is a controversy concerning the crystal structure of BCTO, particularly with respect to the true space group [24,25,29].…”

Structure, electrical, and thermal expansion properties of PZnTe–PZT ternary system piezoelectric ceramics

“…Pb(Mg 0.5 Te 0.5 )O 3 is a compound with complex perovskite structure which was first reported by Bayer . The lattice parameters and phase transformation behavior were studied by Politova and Baldinozzi . Other Te‐containing perovskite compounds (Pb(Zn 0.5 Te 0.5 )O 3 , Pb(Ni 0.5 Te 0.5 )O 3 ) have been reported by Isupov .…”

Digital electron diffraction – seeing the whole picture

“…In any case, we expect the space group to be some subgroup of Pm3m. Tellurium-containing compounds can exhibit ferroelectric or antiferroelectric behaviour (Venevtsev et al, 1974;Politova & Venevtsev, 1975); in terms of functional properties, ferroelectric behaviour is preferable since this leads to piezoelectric, pyroelectric and other useful applica-tions. Since these ferroic properties only exist in materials without a centre of symmetry, determination of the crystal point and space group has direct relevance to technological utility, and electron diffraction has a distinct advantage here.…”