Comprehensive impedance spectroscopy, Raman, and infrared studies of the ferroelectric properties and application of BiFeWO6

Tetragonal double perovskite BiFeWO₆ nanopowders were successfully synthesized via the solid-state reaction technique. Structural characterization using X-ray diffraction (XRD) revealed an average crystallite size of 11.6 nm with a lattice strain of 0.06499. The study of the microstructure of the sample reveals uniform distribution of well-grown grains and presence of all constituent elements in both weight and atomic percentages. Optical properties were investigated through ultraviolet (UV)-visible spectroscopy, which revealed a bandgap energy of 1.41 eV, highlighting its potential for photovoltaic applications. Raman spectroscopy confirmed the presence of all constituent elemental vibrational modes associated with various molecular bonding interactions in the studied material. Dielectric analysis exhibited a Maxwell–Wagner-type polarization effect, indicating its potential as a material with a high dielectric constant and low loss for energy storage devices. The study of impedance plots revealed a negative temperature coefficient of resistance (NTCR) behavior, whereas the electrical modulus study suggested the presence of a non-Debye-type relaxation mechanism. The study of AC conductivity versus frequency and temperature revealed the fact that the conduction mechanism is controlled by thermally activated charge carriers. Again, semicircular Nyquist and Cole–Cole plots confirmed the semiconductor nature and well-supported impedance results. The resistance versus temperature plot showed an NTC thermistor character, indicating that BiFeWO₆ is a strong candidate for temperature sensor devices.