Impedance Spectroscopic Studies on Lead Based Perovskite Materials

Abstract

Impedance spectroscopic measurements were carried out on lead based ferroelectric ceramics, namely PZT, PLZT and PMN-PT, in the frequency range of 0.1 Hz–1 MHz. Spectroscopic plots showed broad peaks, and are found to shift towards higher frequency side. Apart from this, both Z″ and M″ spectroscopic peaks are found to coincide almost in the same frequency region. This indicates approximated-Debye behavior. Frequency dependent conductivity plots show two slopes at lower and higher frequency regions. Low frequency relaxations are found to be non-exponential. Bulk relaxation vs. temperature plots are found to obey Arhenius linear fit. The relaxation at lower frequency and higher are attributed to Kohlrausch-Williams-Watt (KWW) type and migration of slow oxygen and lead vacancies. The results are corroborated to the conduction barrier hopping mechanism and new Eyraud's conductivity model.

Keywords:

• Combined impedance and modulus spectroscopy
• poly-dispersive (non-Debye) relaxation
• conductivity and hopping mechanism

Acknowledgments

One of the author NVP thanks Department of Science and Technology, New Delhi for sanctioning the SERC-DST Fast track Young Scientist Proposals (SR/FTP/PS-32/2003) and thankful to the Siddhartha Academy of General & Technical Education, Vijayawada for giving constant encouragement.