Microstructure and Relaxor Behavior of Dense Fine‐Grain FeTiTaO₆ Ceramics

Abstract

A new type of FeTiTaO6 ceramics with a high density was synthesized by the solid‐state method. X‐ray diffraction and scanning electron microscopy patterns indicate that the specimens exhibit a rutile structure and the mean particle size was about 200–300 nm. The heterovalent substitutions of Fe3+ and Ta5+ at Ti4+ site drive the incipient ferroelectric to the relaxor behavior, and a strong dispersion of the maximum dielectric permittivity appears around Tm, which shifts towards higher temperatures with the increasing frequency. The variation of Tm with frequency follows the Vogel–Fulcher relationship well, wherein Ea=0.068 eV, Tf=508 K, and f0=109 Hz. These results indicate that the nonperovskite‐type FeTiTaO6 ceramic is a promising candidate for lead‐free relaxor ferroelectrics in practical applications.

Dielectric and energy harvesting properties of FeTiNbO6/PVDF composites with reinforced sandwich structure

“…Figure 6a-c presents the measured D-E loops for FTN/ PVDF, BT20-FTN40-BT20, and BT40-FTN40-BT40, respectively. As for the FTN/PVDF, the composites with the 40 vol% of FTN had the significant leakage phenomenon, because of the high conductivity of the FTN, which would limit its operation at higher voltages [33,55]. But, through constructing sandwich structures, leakage current has been suppressed greatly because of the existence of insulating layer.…”

“…An alternative solution, which may address this problem, is to fabricate percolative composites by introducing conductive fillers, such as metal particles [20,21], carbon material [22][23][24][25], or a new type of polar oxide with a giant dielectric permittivity at 10 4 order or above, such as calcium copper titanate (CCTO) [26][27][28] and Li and Ti co-doped NiO (LNTO) [29][30][31] as fillers into an insulating polymer matrix. Except for the popular CCTO and LNTO, rutile type polar oxides such as FeTiTaO 6 [32,33] and FeT-iNbO 6 (FTN) [34,35] also draw much attention recently due to a giant dielectric permittivity with strong relaxor behavior. The superiorities of percolative composites lie in their high dielectric permittivity obtained at relatively low filler content, in which relatively high mechanical strength can be preserved.…”

Crystal structure, photocatalytic and dielectric property of ATiM2O8 (A: Mg, Zn; M: Nb, Ta)

“…Moreover, the addition of titanium in transition-metal niobates and tantalates is limited to the formation of rutile-and trirutile-type structures. In particular, FeTiMO 6 (M; Nb,Ta) [2][3][4] and NiTiNb 2 O 8 [5], both with the rutile-type structure, have drawn interests for their dielectric properties. Recently, we reported the crystal structure and photocatalytic activity of the solid solution, Ni 1-x Co x Ti(Nb 1-y Ta y ) 2 O 8 (0 ≤ x ≤ 1, 0 ≤ y ≤ 1) [6], which had a rutile-type structure for y = 0, a trirutile-type structure for y = 1 and a trirutile-type structure appeared for y ≥ 0.4.…”