  Via a combination of various experimental and theoretical techniques, a
peculiar, identical temperature scale T* is found to exist in all complex
lead-based relaxor ferroelectrics. T* corresponds to a nanoscale phase
transition due to random fields. Interestingly, T* 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.
