Impedance spectroscopic studies in SrBi₄Ti₄O₁₅

Abstract

The impedance measurements have been performed in the temperature range of 30 to 600^oC and the frequency range 1 kHz to 10 MHz on four-layered SrBi₄Ti₄O₁₅. The imaginary components of impedance Z", the electrical modulus <i>M" </i>and ac conductivity have been computed, both as a function of frequency and temperature. The peaks appear in Z" versus

frequency plots and they shift towards lower frequencies at the temperature up to 500 ^oC and above 525 ^oC they shift towards higher frequencies. Similar behaviour is observed in <i>M</i>" versus frequency plots. |Z "| values decrease with increase of temperature, while |<i>M</i>"| values decrease up to 500°C and above 525^oC these values are found to increase with temperature. Complex impedance diagrams are nearly semicircles at higher temperatures. Results are interpreted in terms of possible conductivity mechanisms present in the sample.