Domain structures and correlated out-of-plane and in-plane polarization reorientations in Pb(Zr0.96Ti0.04)O3 single crystal via piezoresponse force microscopy

Pb(Zr1-xTix)O3 single crystal with a low titanium content (x = 4%) was studied by the piezoresponse force microscopy (PFM) and X-ray diffraction (XRD). The XRD studies showed that the crystal faces are orthogonal to the principal cubic axes and confirmed the existence of an intermediate phase between the high-temperature paraelectric (PE) phase and the low-temperature antiferroelectric (AFE) one. A significant temperature hysteresis of phase transitions was observed by the XRD: On heating, the AFE state transforms into the intermediate one at about 373 K and the PE phase appears at 508 K, whereas on cooling the intermediate phase forms at 503 K and persists down to at least 313 K. The PFM investigation was focused on the intermediate phase and involved measurements of both out-of-plane and in-plane electromechanical responses of the (001)-oriented crystal face. The PFM images revealed the presence of polarization patterns switchable by an applied electric field, which confirms the ferroelectric character of the intermediate phase. Importantly, two types of regular domain structures were found, which differ by the spatial orientation of domain walls. The reconstruction of polarization configurations in the observed domain structures showed that one of them is a purely ferroelectric 180° structure with domain walls orthogonal to the crystal surface and parallel to one of the ⟨111⟩ pseudocubic directions. Another one is a ferroelectric-ferroelastic domain structure with the 71° walls parallel to the {101} or {011} crystallographic planes. Remarkably, this domain structure shows correlated out-of-plane and in-plane polarization reorientations after the poling with the aid of the microscope tip

Critical scattering of synchrotron radiation in lead zirconate-titanate with low titanium concentrations

Diffuse scattering in the lead zirconate-titanate single crystal with a titanium concentration of 0.7 at % has been studied by the synchrotron radiation scattering method. Measurements have been performed both in the vicinity of the Brillouin zone center and at the M-point. Highly anisotropic diffuse scattering has been revealed in the paraelectric phase near the Brillouin zone center; diffuse scattering anisotropy is similar to that previously observed in pure lead zirconate. The temperature dependence of this diffuse scattering obeys a critical law with T (c) a parts per thousand 480 K. Diffuse scattering in the vicinity of the M-point weakly depends on temperature; this dependence behaves differently at M-points with various indices

The origin of antiferroelectricity in PbZrO3

Antiferroelectrics are essential ingredients for the widely applied piezoelectric and ferroelectric materials: the most common ferroelectric, lead zirconate titanate is an alloy of the ferroelectric lead titanate and the antiferroelectric lead zirconate. Antiferroelectrics themselves are useful in large digital displacement transducers and energy-storage capacitors. Despite their technological importance, the reason why materials become antiferroelectric has remained allusive since their first discovery. Here we report the results of a study on the lattice dynamics of the antiferroelectric lead zirconate using inelastic and diffuse X-ray scattering techniques and the Brillouin light scattering. The analysis of the results reveals that the antiferroelectric state is a 'missed' incommensurate phase, and that the paraelectric to antiferroelectric phase transition is driven by the softening of a single lattice mode via flexoelectric coupling. These findings resolve the mystery of the origin of antiferroelectricity in lead zirconate and suggest an approach to the treatment of complex phase transitions in ferroics