摘要:

Pulsed-laser-deposited SrTiO3thin films are used as all example to illustrate the effects of strain. oxygen vacancies, and interfacial dead layer on the dielectric and lattice dynamical properties in ferroelectric thin films. We found that strain, both lattice mismatch-induced and due to local defects such as oxygen vacancies, dramatically influences the properties of the thin films. The cubic-to-tetragonal structural phase transition is greatly modified by the strain in the films. Raman scattering shows the symmetry-forbidden optical phonons, indicating the reduction of symmetry. The line shape of the polar phonon shows a Fano asymmetry, which we suggest to be due to the micro polar regions or other local polar structures around the oxygen vacancies. The temperature dependence of the low-frequency complex dielectric constant shows markedly distinct quantum fluctuation behaviors from those of the single crystals. The soft mode is considerably hardened in the thin films compared to the single crystals.

ISSN:1058-4587    

DOI:10.1080/10584580008222236

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

ISSN:1058-4587    

DOI:10.1080/10584580008222215

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor