Dielectric properties and kinetics of induced phase transition in ceramic compounds 16BiScO$_3$-42PbTiO$_3$-42PbMg$_{1/3}$Nb$_{2/3}$O$_3$

The relationship between the depolarization temperatures $T_d$ and the morphotropic phase transition $T_{\mathrm{F}-\mathrm{R}}$ in the relaxor ceramics 16BiScO$_3$-42PbTiO$_3$-42PbMg$_{1/3}$Nb$_{2/3}$O$_3$, as well as the kinetics of nucleation of ordered ferroelectric phases in an electric field applied below the morphotropic phase transition temperature, were studied. The coincidence of these temperatures was found, which is associated with a one-stage transition of the polarized sample to the relaxor phase. It was suggested that possible reasons may be both the closeness of the composition to relaxors with a spontaneous phase transition, in which these temperatures coincide, and large sizes of the polar regions. The field-temperature phase diagram was constructed for cooling the sample in an electric field (FC mode). In the study of time dependences of permittivity in an electric field at room temperature, it was found for the first time that the monoclinic phase after a short time interval of $\sim$ 300 s in high electric fields is transformed into another ferroelectric tetragonal phase. This phase is not stable after the electric field is removed, and the sample returns to its original state before the field was applied.