Investigation of a peculiar relaxor ferroelectric: Na0.5Bi0.5TiO3.
FERROELECTRICS 270 (2002) 1377-1382
Abstract:
The relaxor ferroelectric, Sodium Bismuth Titanate, (Na0.5Bi0.5TiO3), NBT is an A-site substituted distorted perovskite. An extensive temperature-, pressure- and substitution-dependent study of the crystal structure and phase transitions in this compound has been carried out using neutron/x-ray diffraction techniques. This has been complemented with optical, Raman and computational modelling studies.The temperature-dependent investigation shows that NBT undergoes a first phase transition from the high-temperature cubic prototype (Pm (3) over bar m) Phase I to Phase II of tetragonal symmetry (P4bm) and then a second one with strong diffuse character to Phase III of rhombohedral symmetry (R3c). The high-pressure study of NBT has revealed an interesting and unusual relaxor-to-antiferroelectric (R3c --> Pnma) phase transition. Structural variations as a function of temperature and doping across the (Na1-xKx)(0.5)Bi0.5TiO3 (NKBT) series have also been established.Nomenclature of magnetic, incommensurate, composition-changed morphotropic, polytype, transient-structural and quasicrystalline phases undergoing phase transitions.: II.: Report of an IUCr Working Group on Phase Transition Nomenclature (vol A57, pg 614, 2001)
ACTA CRYSTALLOGRAPHICA SECTION A 58 (2002) 79-79
Optical rotation in RbTiOAsO4 (point group mm2)
ZEITSCHRIFT FUR KRISTALLOGRAPHIE 217:1 (2002) 1-7
Response to K. H.!Kuo's Comments on quasicrystalline phases and examples of quasicrystalline phase nomenclature in Nomenclature of magnetic, incommensurate, composition-changed morphotropic, polytype, transient-structural and quasicrystalline phases undergoing phase transitions.: II.: Report of an IUCr Working Group on Phase Transition Nomenclature by J.-C.!Toledano et al. (2001).: Acta Cryst. A57, 614-626
ACTA CRYSTALLOGRAPHICA SECTION A 58 (2002) 210-210