Structure, dielectric, vibrational, and optical properties of lead-free double perovskite Bi2FeMnO6.

The solid-state reaction technique was executed to form a hexagonal double perovskite Bi₂FeMnO₆ nanopowder. X-ray diffraction (XRD) analysis gives information regarding the product's average crystallite size of 27.9 nm and lattice strain of 0.00125, respectively. The Ultra-Violet (UV) visible spectroscopy data provides a band gap energy of 2.49 eV, which may be a suitable range for photovoltaic applications. Fourier Transform Infrared (FTIR) spectroscopy data analysis reveals the presence of all constituent atomic vibration bands. The dielectric measurements confirmed the presence of the Maxwell-Wanger type of dispersion. The negative temperature coefficient of resistance (NTCR) character is well understood from impedance spectroscopy. The electrical modulus results indicate the presence of a non-Debye-type of relaxation mechanism in the sample. Analyzing ac conductivity data reveals the thermally activated conduction process. The sample's semi-conducting character was confirmed by both Nyquist and Cole-Cole plots. [ABSTRACT FROM AUTHOR]