Nanostructures formation in ferroelectrics in the process of phase transformation

Abstract

Inhomogeneous states caused by the coexistence of the ferroelectric (FE) and antiferroelectric (AFE) phases in lead–zirconate–titanate based solid solutions have been investigated. It has been found that the domains of the FE and AFE phases with sizes of the order of 20 nm to 30 nm coexist in the bulk of the samples due to a small difference in the free energies of these phases. The coherent character of the interphase boundaries (IPBs) leads to the concentration of the elastic stresses along these boundaries. These elastic stresses cause the local decomposition of the solid solution and formation of segregates near the IPBS due to the condition that equivalent positions of the crystal lattice are occupied by the ions with different sizes. The sizes of the segregates formed in this way are of the order 8 nm to 15 nm. Some physical effects caused by the presence of these segregate nanostructures are analyzed and discussed.