| Structural, microstructural, dielectric, transport, and optical properties of modified bismuth ferrite |
| S. K. Sourav1, S. K. Parida2, R. N. P. Choudhary2, Umakant Prasad1 |
1Department of Physics, T. N. B. College , T. M. Bhagalpur University , Bhagalpur 812007, Bihar, India
2Department of Physics, ITER, Siksha O Anusandhan Deemed to Be University, Bhubaneswar 751030 , India |
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Received: November 5, 2022; Revised: January 30, 2023 Accepted: March 6, 2023. Published online: April 18, 2023. |
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| ABSTRACT |
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In this communication, the synthesis (solid-state reaction) and characterization (XRD, SEM, EDX, and IS) of the (1 − x ) BiFeO3−x (BiNaKTiMnO3), (x= 0.05 and 0.1) ceramics were reported. The structural analysis suggests a rhombohedral crystal symmetry (#R3c) with an average crystallite size of 39.6 nm and micro-lattice strain of 0.000401 in x = 0.05 sample, whereas average crystallite size of 46.6 nm and lattice strain of 0.00133 in x = 0.1 sample, respectively. The growth and distribution of the grains and the position of grain boundaries were studied from a scanning electron microscope (SEM). The purity and compositional analysis of the prepared samples were checked from an energy-dispersive X-ray analysis (EDX) image. The study of the Fourier-transform infrared spectroscopy (FTIR) spectrum suggests the presence of a stretching band of the constituent elements in the modified bismuth ferrite. The presence of the Maxwell–Wanger type of dispersion was confirmed by a dielectric study. The investigation of impedance as a function of temperature and frequency reveals the existence of a negative temperature coefficient of resistance (NTCR). A non-Debye kind of relaxation mechanism is revealed by electric modulus analysis; however, a thermally induced relaxation process is confirmed by an ac conductivity study. The semi-circular arcs in the Nyquist and Cole–Cole plots indicate that the sample is semiconducting. BNKTM 5% has an energy bandgap of 2.9 eV, while BNKTM 10% has an energy bandgap of 2.7 eV, according to UV–visible spectra. The fi eld-dependent hysteresis loop is analogous to the onset of ferroelectricity. |
| Key words:
(1 − x )BiFeO 3 − x (BiNaKTiMnO3) · Rhombohedral · Maxwell–Wanger dispersion · Non-Debye relaxation · Thermally activated relaxation · Nyquist plots |
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