DIELECTRIC AND CRYSTALLOGRAPHIC STUDY OF THE LEAD MAGNOTANTALATE RELAXOR

The complex perovskite Pb(Mg1/3Ta2/3)O-3 is one of the first relaxer f erroelectric compounds that was investigated. The present study report s some new important data of dielectric properties and structure chara cteristics. A Vogel-Fulcher behavior is observed for the frequency dep endence of T-max with a freezing temperature T-f = 144K. Dielectric me asurements under high electric field show that the dielectric constant decreases as the field increases, but T,, remains unchanged. The x-ra y crystallographic study reveals a cubic structure down to liquid nitr ogen temperature. The temperature dependence of the cell parameter is determined and the cluster nucleation temperature is thus estimated to be about 573K. The difference in relaxer behavior between Pb(Mg1/3Ta2 /3)O-3 and Pb(Mg1/3Nb2/3)O-3 is discussed.