Impact of B-site Substitution of Transition Metal (Fe and Mn) on the Structural, Electrical, and Magnetic Properties of Tungsten Bronze Ferroelectric Ceramic

The solid-state reaction approach was used to synthesize Ba_0.95Sr_0.05Ca₅Ti_2−xM_xNb₈O₃₀ (where M represents Fe and Mn and x is 0 and 0.05) in order to compare the variations in the structural and dielectric properties of the ferroelectric material. The structural investigation was carried out using x-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy. The orthorhombic structure with Pbcn space group revealed by the XRD investigation was validated by Rietveld refinement. The FTIR spectroscopy results were in good agreement with the reported phase. Analysis of the electrical properties was carried out by complex impedance spectroscopy. The results of transition metal doping with both Fe and Mn with regard to the dielectric permittivity as a function of frequency showed an improvement in the dielectric characteristics, while Mn exhibited a higher dielectric constant than Fe. The pure sample showed a lower transition temperature than the Fe- and Mn-doped sample. Analysis of the magnetic characteristics obtained from vibrating-sample magnetometry (VSM) revealed that doping enhanced the magnetic properties. This approach thus shows excellent potential for high-temperature operation, achieving good temperature stability via transition metal doping.