Phase transitions due to polar region structure in disordered ferroelectrics

We show clear experimental evidence for two phase transitions in titanium doped lead magnesium niobate compositional disordered ferroelectrics. One is the diffuse phase transition near the temperature of the dielectric permittivity maximum, which is often called the characteristic of relaxor ferroelectrics (relaxors). Another is a first-order transformation from relaxor ferroelectric to normal ferroelectric, corresponding to a zero-field spontaneous polar micro-macrodomain switching. According to X-ray diffraction (XRD) measurements, thermal analysis and transmission electron microscope (TEM) results, a dynamic behavior of polar microregions is necessary to explain the phenomena, which is more similar to a stress induced martensitic transformations form cubically stabilized perovskite parent-phase. It is also observed that the dynamic behavior of polar regions was influenced by the titanium doping.