Size effects on static and dynamic properties of ferroelectric nanoparticles

作者：Michael Th^*; Trimper S; Wesselinowa J M

来源：Physical Review B, 2007, 76(9): 094107.

DOI：10.1103/PhysRevB.76.094107

Ferroelectric nanoparticles are described by a microscopic model which enables one to find the macroscopic polarization as well as the excitation energy of the soft mode and its damping with dependence on the temperature and the size of the particles. The constituents of the material are arranged in shells, and their interaction depends on both the coupling at the surface and within the bulk. A Green's function technique in real space is applied to analyze the Ising model in a transverse field, which is modified in such a manner as to be able to study also spherical nanoparticles. Furthermore, we investigate the influence of size effects on the critical temperature. Whereas the excitation energy is lowered significantly with decreasing particle size, the damping is enhanced. Additionally, we consider the influence of defects on the excitation spectrum. The theoretical results are compared with experimental data.

• 出版日期2007-9