Grain and Grain-Boundary Study of Acceptor Doped SrTiO₃ Ceramics Using Impedance Spectroscopy

Impedance spectroscopy has been used to characterize grain and grain-boundary resistivities of Ni-doped SrTiO ₃ ceramics. The role of grain boundary was changed with Ni-doping concentration. The phenomenon was also interpreted by accounting for microstructural differences. The corresponding relaxation times were also used to confirm the interpretation of complex impedance spectra. Overlapping of Grain boundary and electrode relaxation processes can be separated above about 400°C. Admittance spectra may be suitable to extract grain boundary impedances at relatively low temperatures. The values of grain and grain-boundary activation energy obtained by this method were relatively close to those reported earlier.

Keywords:

• SrTiO₃
• acceptor
• impedance spectroscopy
• grain
• grain boundary

Acknowledgments

Paper originally presented at AMF-4, Bangalore, India, December 12-15, 2003.