The phase transformation, dielectric and pyroelectric properties of (PbBa)(Zr,Sn,Ti)O3 solid solutions with compositions near AFE/RFE phase boundary

Ba-modified lead zircono-stanno-titanate (Pb0.87La0.02Ba0.1)(Zr0.6Sn0.4-x, Ti-x)O-3 (0.04less than or equal toxless than or equal to0.20)solid solutions were investigated by measurements of dielectric spectroscopy and pyroelectric current. It is found that specimens with 0.04less than or equal toxless than or equal to0.07 are in antiferroelectric tetragonal phase (AFE(t)), but specimens with 0.09less than or equal toxless than or equal to0.20 are ferroelectric relaxors (RFE). Therefore, there is a new AFE/RFE phase boundary. In the temperature-Ti content( x) phase diagram, FE-AFE-PE (paraelectric phase) triple-phase point with the lowest phase transition temperature has been observed for the composition of x = 0.09. For AFE(t) ceramics (x less than or equal to 0.07), a particular diffuse phase transition and polar relaxor behaviour is observed at low temperatures, within which AFE(t) could be induced to a metastable ferroelectlic state (FEin) by applying an external electric field. FEin. was transformed to AFE(t) and PE states separately with the increase of temperature, resulting in two pyroelectric peaks. Furthermore, FE-AFE-PE triple-phase point has been observed in the phase diagram of temperature- electric bias field (E). Finally, the experimental results have been well explained on lattice dynamics, considering nano-size phase separation in complex compounds.