Intermediate temperature scale T ∗ in lead-based relaxor systems

Via a combination of various experimental and theoretical techniques, a peculiar, identical temperature scale ${T}^{\ensuremath{\ast}}$ is found to exist in all complex lead-based relaxor ferroelectrics studied by us. ${T}^{\ensuremath{\ast}}$ corresponds to a nanoscale phase transition associated with random fields. Interestingly, ${T}^{\ensuremath{\ast}}$ also exists in other oxides with extraordinary properties, such as giant magnetoresistivity or superconductivity. By analogy with such latter systems, the giant piezoelectricity related to relaxors might originate from proximity competing states effect.