Critical temperatures of 70%Pb(Mg_(1/3)Nb_(2/3))O_3-30%PbTiO_3 thin films investigated by dielectric, ferroelectric, and structural measurements

摘要

The authors have investigated the temperature dependence of the ferroelectric, dielectric, and structural properties of 70%Pb(Mg_(1/3)Nb_(2/3))O_3-30%PbTiO_3 thin films. Two critical temperatures were evidenced. The first one occurring around 410 K corresponds to the bulk paraelectric-ferroelectric phase transition and the second one around 200 K is rather related to a self-arrangement of small domains into macrodomains in order to minimize elastic energies. A multiscale domainlike structure is induced and the temperature evolution of such complex structure can be revealed through pronounced changes occurring in the nonlinear dielectric susceptibility.