Effects of V Substitution on Dielectric and Polarization Properties for Sr_0.5Bi_2.25Na_1.25(Nb_3−xV_x)O₁₂ Ceramics

Abstract

1.25 (Nb 3Àx V x )O 12 ceramics were investigated in this study. From the X-ray powder diffraction results, no secondary phase was detected in the composition range of 0-0.075. The remanent polarizations (P r ) of the samples in the composition range of 0-0.03 were improved by the V substitution for Nb and the highest P r value of approximately 15 lC/cm 2 was obtained at x 5 0.03; it was noted that the V substitution for Nb was effective in improving the P r values in this ceramics. On the other hand, the coercive fields (E c ) of the samples were on the order of approximately 40 kV/cm in such a composition range. Moreover, the anomalous variations in the dielectric constant were observed in the composition range of 0-0.075. Also, it was observed that the dielectric loss increased drastically at the temperature of approximately 5001C.

Synthesis and Ferroelectric Properties of Bi4.5Sr0.5Ti4Fe0.5-xVxO15Ceramics

“…When comparing the P r value of the sample at x = 0.03 with that of the sample at x = 0, the improvement in the P r value was recognized by the V substitution, though the remarkable differences in the E c values of the samples at x = 0 and 0.03 was not observed. In the case of small amount of V-substituted ferroelectric materials, it is reported that the ratting in the BO 6 octahedron in the [A n-1 B n O 3n+1 ] 2− perovskite block which relates with the structural distortion and the improvement in the sinterability enhances the ferroelectric properties of the materials [6,12]. The temperature dependences of dielectric constant of BSTVF at 1 MHz are shown in Fig.…”

“…As a result, the microstructure of BSTVF at x = 0.03 consists of fine grains of ∼6-10 µm as determined from the FE-SEM observations. The grain size of BSTVF at ceramics [6]. The microstructure analysis of BSTFV indicates that the small amounts of V substitution may effective in enhancing the grain growth of BSTFV.…”

“…The crystal structure, ferroelectric property, and the temperature dependence of the dielectric constant have been reported [2][3][4], whereas the details on the Bi 4.5 Sr 0.5 Ti 4 Fe 0.5 O 15 (BSTF) compound which consist of the mixture of BTF and SBT compounds have not been evaluated. In addition, it is also reported that the small amount of V doping is effective in enhancing the ferroelectric properties of the compound [5][6][7][8][9], though the influences of V substitution for Fe on the ferroelectric properties and the crystal structure of BSTF have not been clarified to date. Thus, the Bi 4.5 Sr 0.5 Ti 4 Fe 0.5-x V x O 15 (BSTFV, x = 0-0.05) ceramics were synthesized and the ferroelectric properties of the ceramics were characterized in this study.…”