Order-disorder nature of ferroelectric BaTi2O5

Order-Disorder Reactions in the Ferroelectric Perovskites

The perovskites Pb(SclpNblp)O, and Pb(SclpTalp)O, can be obtained in a disordered state by means of a synthesis a t high temperature (1 250 to 1600 "C). Ordering of the trivalent and pentavalent ions occurs during annealing a t lower temperatures. The kinetics of this ordering process are investigated by means of X-ray diffraction, dielectric polarisation, and DSC measurements. The ordering pro...

Order and Disorder in Nature

Eight-potential-well order-disorder ferroelectric model and effects of random fields

An eight-potential-well order-disorder ferroelectric model was presented and the phase transition was studied under the mean-field approximation. It was shown that the two-body interactions are able to account for the first-order and the second order phase transitions. With increasing the random fields in the system, a first-order phase transition is transformed into a second-order phase transi...

The Nature of Domain Stabilization in Ferroelectric Perovskites

Ferroelectric perovskites, such as Pb(Ti,Zr)O, and BaTiO,, are subject to ageing effects, caused by a gradual stabilization of the ferroelectric domain structure. We studied the development of this stabilization in Mn-doped BaTiO, monocrystals having a special kind of domain structure. We concluded from measurements of the growth of the internal bias field E, and the change of the sideways 180”...

Ferroelectric order in individual nanometre-scale crystals.

Ferroelectricity in finite-dimensional systems continues to arouse interest, motivated by predictions of vortex polarization states and the utility of ferroelectric nanomaterials in memory devices, actuators and other applications. Critical to these areas of research are the nanoscale polarization structure and scaling limit of ferroelectric order, which are determined here in individual nanocr...