Influence of Na/Bi excess on structural, dielectric and multiferroic properties of lead free (Na_0.5Bi_0.5)_0.99La_0.01Ti_0.988Fe_0.012O₃ ceramic

Highlights: • Lead free NBLTF is synthesized with varying stoichiometric ratio of Na and Bi. • Structural analyses are performed using XRD, SEM, FT-IR and RAMAN measurements. • Dielectric properties with frequency and temperature have been studied. • Ferroelectric and magnetic properties at room temperature have been studied. - Abstract: (Na_0.5Bi_0.5)_0.99La_0.01Ti_0.988Fe_0.012O₃ (NBLTF) ceramic has been prepared by sol–gel method without and with 10 mol% excess of Na and Bi. Structural analysis of NBLTF samples has been carried out by XRD, FT-IR and Raman spectra. X-ray diffraction patterns of NBLTF samples confirm single phase perovskite structure having rhombohedral symmetry. FT-IR and Raman spectra exhibit similar characteristic bands for both NBLTF samples which confirm the formation of perovskite structure. Comparatively high intensity and shifting of Raman bands in NBLTF sample having excess mol% of Na and Bi suggest dense crystal growth which is consistent with microstructural properties of the sample and density measurements. Bi loss during sintering process and the dense crystal growth is reported to affect the dielectric, magnetic and ferroelectric properties in synthesized samples