Synthesis and characterization of La-modified bismuth ferrite: [Bi1 − xLaxFeO3] (x = 0.04, 0.08, and 0.12)

This article reports the synthesis and electrical characterization of La-modified BiFeO₃[Bi_1 − xLa_xFeO₃] (x = 0.04, 0.08, and 0.12) by the solid-state reaction method. It is shown that every sample belongs to the R3c space group and rhombohedral structures. The surface compositions and morphology analyzed by FESEM and EDX reveal the creation of a very compact sample with a uniform grain distribution. These analyses are done from a temperature range (25 °C–500 °C), and the frequency is taken in the range of (1 kHz–1 MHz). The activation energy of the sample was calculated from the temperature-dependent ac conductivity graph. The frequency-dependent conductivity graph fitted well with Jonscher’s power law, and the conduction mechanism is due to the hopping of charge carriers. The frequency-dependent modulus plot suggests a non-Debye type nature of the synthesized sample. The frequency-dependent real and imaginary part of the impedance was plotted (Nyquist Plot), showing a semicircular arc that describes the semiconducting behavior of the substance. Hence, the material for temperature-based sensors is highly supported by the NTCR behavior of the compound.