A multifunctional transition metal based double perovskite Ba2(FeW)O6: Structural, microstructural, optical, electrical and ferroelectric properties
S. Mishra, R. N. P. Choudhary, S. K. Parida
Abstract
In this article, synthesis (solid-state reaction) and characterizations (XRD, SEM-EDX, RAMAN, UV–Vis, LCR & P-E measurements) of a polycrystalline double perovskite Ba 2 (FeW)O 6 are reported. The prepared sample crystallizes in tetragonal symmetry with an average crystallite size of 60.7 n m and lattice strain of 0.00045 respectively. Vibrational modes of the molecules in the prepared sample are investigated using Raman spectroscopy . Analysis of scanning electron microscope (SEM) and energy dispersive analysis of x-ray (EDX) supports homogenous distribution of grains and compositional consistency. Optical investigation calibrates direct energy bandgap of 2.72 eV; which may be suitable for photocatalytic and photovoltaic devices . Dielectric , impedance, and modulus spectra have been studied over a wide range of frequencies (1 kHz–1 MHz) and temperatures (25 °C–500 °C). Wide dielectric dispersion at low-frequency encounters space charge polarization with the Maxwell-Wager effect. Study of impedance plots reveals negative temperature coefficient resistance (NTCR) character while existence of non-Debye relaxation mechanism is confirmed from modulus plots. Frequency dependence ac conductivity obeys Jonscher's Power Law (JPL) and confirms the presence of a non-overlapping small polaron and correlated barrier hopping process (CBH). The study of activation energy (E a ), sensitivity factor (α) and thermistor constant (β) values from resistance versus temperature supports NTC thermistor behaviour and explore the possible applications related to temperature-based sensors.