Properties of Na0.5Bi0.5TiO3 Ceramics Modified with Fe and Mn

Abstract

Na0.5Bi0.5TiO3 (NBT) and Fe- and Mn-modified NBT (0.5 and 1 mol%) ceramics were synthesized by the solid-state reaction method. The crystal structure, dielectric and thermal properties of these ceramics were measured in both unpoled and poled states. Neither the addition of iron/manganese to NBT nor poling changed the average crystal structure of the material; however, changes were observed in the short-range scale. The changes in shapes of the Bragg peaks and in their 2Θ-position and changes in the Raman spectra indicated a temperature-driven structural evolution similar to that in pure NBT. It was found that both substitutions led to a decrease in the depolarization temperature Td and an increase in the piezoelectric coefficient d33. In addition, applying an electric field reactivated and extended the ferroelectric state to higher temperatures (Td increased). These effects could be the result of: crystal structure disturbance; changes in the density of defects; the appearance of (FeTiˈ-), (Mn′Ti-V••O) and (Mn″Tii-V••O )—microdipoles; improved domain reorientation conditions and instability of the local polarization state due to the introduction of Fe and Mn into the NBT; reinforced polarization/domain ordering; and partial transformation of the rhombohedral regions into tetragonal ones by the electric field, which supports a long-range ferroelectric state. The possible occupancy of A- and/or B-sites by Fe and Mn ions is discussed based on ionic radius/valence/electronegativity principles. The doping of Fe/Mn and E-poling offers an effective way to modify the properties of NBT.

Effects of Mn doping on the conduction mechanism and dielectric nonlinearity of Na0.5Bi0.5TiO3 thin film

“…Manganese doping is widely acknowledged as an effective method for ameliorating the detrimental effects of element volatilization in NBT-based films [12][13][14]. For instance, it has been demonstrated that Mn-doped NBT films have leakage current densities up to four orders of magnitude lower than those observed in pure NBT films [12].…”

Electrophysical Properties of the Three-Component Multiferroic Ceramic Composites

“…In recent years, well-known ceramic materials with functional properties, e.g., [ 1 , 2 , 3 , 4 , 5 , 6 ], have constituted various engineering materials with versatile applications in modern microelectronics [ 7 , 8 ]. These materials include multiferroic composite materials obtained based on ferroelectric and magnetic compounds [ 8 , 9 , 10 , 11 , 12 , 13 ].…”