NMR evidence for the coexistence of order-disorder and displacive components in barium titanate.
A quadrupole coupling induced 47Ti and 49Ti satellite background which transforms into well-defined satellite lines below T(c) in the ferroelectric phase has been observed in the cubic phase of an ultrapure BaTiO3 single crystal. The results demonstrate the coexistence of a displacive and order-disorder component in the phase transition mechanism and tetragonal breaking of the cubic symmetry due to biased Ti motion between off-center sites in the paraelectric phase above T(c).
Zalar
Bostjan
B
J. Stefan Institute, University of Ljubljana, Jamova 39, 1000 Ljubljana, Slovenia.
Laguta
Valentin V
VV
Blinc
Robert
R