Electrical properties of Gd-modified PZT (MPB) ceramics

摘要

The polycrystalline samples of gadolinium (Gd)-modified lead-zirconate-titanate (Pb$_{1?x}$Gd$_x$(Zr$_{0.52}$Ti$_{0.48})_{1?x/4}$O$_3$) ($x$ = 0, 0.07, 0.10 and 0.12) (PGZT) ceramics near morphotropic phase boundary (MPB) were prepared by high-temperature solid-state reaction route. Electrical properties such as impedance ($Z$), modulus ($M$) and conductivity ($sigma$) of the materials have been investigated within a wide range of temperature and frequency. Complex impedance spectroscopy (CIS) studies show that materials exhibit bulk (grain) resistive contributions, negative temperature coefficient of resistance (NTCR) and non-Debye-type dielectric relaxation. The nature of temperature and frequency dependence of conductivity follows Jonscher’s universal power law. $J–E$ characteristics reveal that the materials exhibit semiconducting behaviour and allow a very small leakage current to pass through them.