Relaxation mechanism and conductivity studies of lead-free ceramics: Fe1/2(NaLi)1/4TiO3.

A single-phase lead-free ferroelectric compound, Fe 1 / 2 (NaLi) 1 / 4 TiO3, is found at room temperature. The solid state reaction technique helps to process the sample at the calcination and sintering temperatures of 900 and 950 ∘ C for 4 h respectively. The desired phase and crystal structure formation of the prepared sample are confirmed by analysis of X-ray diffraction (XRD) data and are found to be in orthorhombic structure. The correlation among phase formation and physical properties has been established by using complex impedance spectroscopy (CIS) method over a wide range of frequencies (from 100 Hz to 1 MHz) and different temperatures (25–280 ∘ C). The overlap depressed semicircular arcs represent the association of grain and grain boundary effects in the material. Activation energy (E a) is noted to be 1 eV for the prepared sample. The frequency dependent ac conductivity is followed by Jonscher's universal power law. DC conductivity versus temperature graph also indicates the negative temperature coefficient of resistance (NTCR) behavior of the material. [ABSTRACT FROM AUTHOR]