Effects of poling on the electrical and electromechanical response of PMN–PT relaxor ferroelectric ceramics

Abstract

The dielectric and piezoelectric response of the Pb(Mg1/3Nb2/3)O3–xPbTiO3 (PMN–PT) polycrystalline ceramics after different poling procedures is examined and explained with respect to the phase composition and the domain structure. In the monoclinic (M) compositions a twice lower AC poling field is needed for a similar piezoelectric coefficient (d33) relative to DC poling. The high efficiency of AC poling of the M phase is assigned to its unique structure with low-angle nanodomain walls that are highly responsive to external fields and move in a ‘cascade-like’ motion, contributing to strains up to 0.5%. While the highest d33 is achieved at the morphotropic phase boundary (MPB), the dielectric permittivity of all room-temperature poled samples reached its peak on the tetragonal side of the MPB. The latter is assigned to the broadening of the MPB when poling above the inclined MPB, which can thus be manipulated by the proper poling conditions.

Keywords

• Relaxor ferroelectric ceramics
• Piezoelectric coefficient
• Dielectric permittivity
• Morphotropic phase boundary (MPB)
• Monoclinic nanodomains