Nanostripe domains in CaCu3Ti4O12: Its origin and influences on high permittivity response

Abstract

Internal nanodomains in the form of stripe or nanostripe domains (NSDs) have been found in high permittivity CaCu3Ti4O12 (CCTO) prepared by ceramic route. High resolution transmission electron microscopy study detects plane defects along the domain boundaries. Electron diffraction patterns indicate the existence of probable twinning in CCTO, resulting plane defects. X-ray photoelectron spectroscopy studies also detect Cu1+ and Ti3+ demonstrating the presence of compositional disorder in CCTO which leads to lattice dislocations along the domain boundary regions. Highly disordered plane defects are responsible for creation of NSDs and act as insulating barriers. Thus, high permittivity is achieved through internal barrier layer capacitance within CCTO grains. Present observation of NSDs in CCTO and their origin finally confirm the extrinsic mechanism of the huge dielectric response of CCTO ceramic.