High dielectric constant and low temperature ferroelectric-phase-transition in Ca, Pb co-doped BiFeO3

Abstract

BiFeO3 was co-doped with (Ca, Pb) to obtain Bi1-x(Ca1/2Pb1/2)xFeO3 (x = 0, 0.1 and 0.3) and their structural, morphological, dielectric and ferroelectric properties were studied. The temperature dependent (from 173 to 573 K) dielectric permittivity showed that samples have colossal dielectric constant (CDC) around room temperature. The pure sample had no signs of ferroelectric-phase-transition peak whereas the co-doped samples showed signs of ferroelectric-phase-transition-induced dielectric anomaly with an extremely huge intensity over 106 beyond 573 K. thus, suitable doping of (Ca, Pb) has significantly reduced the Curie temperature towards lower temperature range 536 and 516 K for samples with x = 0.1 and 0.3.

Keywords

• Ferroelectricity
• Colossal dielectric
• Dipole relaxation
• Maxwell-Wagner relaxation
• Impedance analysis
• Interfacial response