phase boundary and electrical properties of lead-free (1-x)BaTi[O.sub.3]-xBi([Li.sub.1/3][Ti.sub.2/3) [O.sub.3] ceramics," Journal of Applied Physics, vol.
region exists on the T-x phase diagram around x [approximately equal to] 0.35 wherein several phases can come about: the cubic, pseudo-cubic, tetragonal, and rhombohedral .
Relaxor based ferroelectric single crystals, such as Pb([Mg.sub.1/3][Nb.sub.2/3])[O.sub.3]-xPbTi[O.sub.3] (PMNT or PMN-xPT) and Pb([Zn.sub.1/3][Nb.sub.2/3])[O.sub.3]-xPbTi[O.sub.3] (PZNT or PZN-xPT), have ultrahigh electromechanical coupling factor [k.sub.33] (>94%) and piezoelectric constant [d.sub.33] (>2500 pC/N) near the morphotropic
phase boundary at room temperature [5-9].
Hoffmann, "Temperature dependence of poling strain and strain under high electric fields in LaSr-doped morphotropic
PZT and its relation to changes in structural characteristics," Acta Materialia, vol.
A Common dental morphotropic
factor, the Carabelli cusp.
This theory is supported by the observations of intermediate phases near the morphotropic
phase boundary (MPB), for example, monoclinic [M.sub.A] and [M.sub.C] phases (space group Cm and Pm, resp.) .
Cann, "The morphotropic
phase boundary and dielectric properties of the xPb([Zr.sub.1/2][Ti.sub.1/2])O3-(1-x)Pb([Ni.sub.1/3][Nb.sub.2/3])[O.sub.3] perovskite solid solution," Journal of Applied Physics, vol.
Ren, "Elastic, piezoelectric, and dielectric properties of Ba([Zr.sub.0.2][Ti.sub.0.8])[O.sub.3]-50 ([Ba.sub.0.7][Ca.sub.0.3])Ti[O.sub.3] Pb-free ceramic at the morphotropic
phase boundary," Journal of Applied Physics, vol.
It is used on a wide scale mainly due to its unique properties at the morphotropic
phase boundary (MPB), at a composition where the PZ: PT ratio is almost 1: 1.
In particular, knowledge of cation off-center displacements in perovskites, which depend on the local chemical environment, enables the prediction of Curie temperature, relaxor dispersion, and the location of morphotropic
phase boundaries--all of which have major impacts on the functional performance of ferroelectrics.
The most interesting for application is the ([K.sub.0.5][Na.sub.0.5])Nb[O.sub.3] compound on the morphotropic
phase boundary [1-3] the ferroelectric phase transition (PT) in which proceeds at [T.sub.c] [approximately equal to] 670 K.
On the morphotropic
phase boundary at x = 0.18, the lattice parameters and unit cell volume change by jump .