Phase transition in relaxor ferroelectrics studied by mechanical measurements

We report the mechanical properties of [(1-x)%]Pb(Mg1/3Nb2/3)O-3-x%PbTiO3 ceramics with PbTiO3 content changed from 23% to 0% measured at the vibration frequency of about 1 kHz. Two modulus kinks can be observed in any of the samples. The kink appears at higher temperature can be attributed to the stress-induced relaxation of nanodomains. Another modulus kink at a lower temperature appears near the Vogel-Fulcher freezing temperature. An associated internal friction peak can also be observed at this temperature. This kink and the internal friction peak can be explained to be due to a ferroelectric phase transition, which becomes weaker with the decrease of PbTiO3 content. (C) 2003 American Institute of Physics.