Structural, dielectric, and multiferroic properties of (Bi0.5K0.5)(Fe0.5Nb0.5)O3

Abstract

A polycrystalline sample of (Bi0.5K0.5)(Fe0.5Nb0.5)O3 was prepared using a mixed oxide at 1000 °C. The preliminary structural analysis using X-ray diffraction data of the compound indicates the formation of a single-phase rhombohedral structure similar to that of parent BiFeO3. Microstructural and elemental analysis using a scanning electron micrograph and energy-dispersive X-ray spectroscopy, respectively, were carried out at room temperature with higher magnification exhibiting a uniform distribution of grains and stoichiometry. The appearance of hysteresis loops (P–E) confirms the existence of ferroelectricity of the sample with a high remnant polarization of (2Pr) 17.76 μCcm−2. Using impedance spectroscopy, the electrical properties of the material were investigated at a wide range of temperature (25–500 °C) and frequencies (1 kHz – 1 MHz) suggesting dielectric non-Debye-type relaxation in the material. The nature of the Nyquist plot ([Formula: see text] ∼ [Formula: see text]) shows the dominance of the grain contribution in the impedance. The bulk resistance of the compound decreases with increasing temperature, like that of a semiconductor, which shows a negative temperature coefficient of resistance (NTCR) behavior. The frequency dependence of AC conductivity suggests that that the material obeys Jonscher’s power law. Magnetic hysteresis (M–H) loop shows very weak ferromagnetic behavior at room temperature.