Relationship between Crystal Structures and the Relaxor Property of SrBi₂(Ta_2–xV_x)O₉ Ceramics

Abstract

Here, V2O5 was used to substitute Ta2O5 in SrBi2Ta2O9 (SBT) and SrBi2(Ta2–xVx)O9 (SBTV) ceramics were formed. This study revealed that the substitution of Ta2O5 by V2O5 enhances the maximum dielectric constant (εm), increases the transition temperature, and reduces the sintering temperature of SBT ceramics. The diffraction intensity of c-axis-preferred orientation of SBTV ceramics increases with the increase in V2O5 concentration and sintering temperature. Disk-type grains were observed in the SBTV ceramics at higher sintering temperatures. By the Curie–Weiss law and modified Curie–Weiss law, the phase transitions of the SBTV ceramics were discussed. The dielectric properties of SBTV ceramics revealed that the relaxor-type ferroelectric characteristics became more obvious than the normal-type ferroelectric characteristics at high V2O5 concentrations and sintering temperatures. Raman spectroscopy was successfully used to study the lattice vibrational modes and structural transitions of SBTV ceramics. The spectra proved that as V2O5 was added to SBTV ceramics the octahedral TaO6 and VO6 structures exhibited a high frequency mode.

Structural and Electronic Effect Driven Distortions in Visible Light Absorbing Polar Materials ATa2V2O11 (A = Sr, Pb)

“…We accessed the dielectric constants at their static limit for an ideal single crystal at T = 0 K, and those parameters were practically the same (ε rSTVO = 21 ≈ ε rPTVO = 22). We note that the obtained values are lower than those detected for SBT compositions enriched with vanadium content 45 probed at a low frequency and close to the room temperature limit. Yet, it is known that the peak dielectric constant of SrBi 2 (Ta 2−x V x )O 9 ceramics is the higher the state of doping for a wide range of temperatures; therefore, corresponding measurements are worth to consider as a perspective for future studies.…”

“…Generally, the vanadium-incorporated SBT demonstrates enhanced dielectric properties , reaching the extremum at the Curie temperature. We accessed the dielectric constants at their static limit for an ideal single crystal at T = 0 K, and those parameters were practically the same (ε rSTVO = 21 ≈ ε rPTVO = 22).…”

High Entropy Oxide Relaxor Ferroelectrics

“…However, the existence of phase segregation and the formation of undesired impurity phases are significant disadvantages associated with a large number of chemical dopants and the mixing of multiple perovskites. [28][29][30][31][32][33][34][35][36][37][38][39] With the complexity of the single phase formation in multi-cation doped-RFE crystals, synthesizing single crystal RFEs with a large number of different cations on the A-and/or B-sites without disrupting crystallinity or structural phase would be an exceptional tool towards designing high-performance RFEs for piezoelectric, pyroelectric, and tunable dielectric applications. 40 The development of an entropy-stabilization approach for synthesizing single crystal ABO3 perovskite films with 5 or more cations at the A-and/or B-sites [41][42][43][44][45] is a promising route to explore how extreme levels of microscopic disorder perturb the polar ordering.…”

“…To create high-performance RFE perovskite oxides, chemical modificationas an extrinsic substitutional defecthas been extensively used to create compositional disorder and to tailor the relaxor behavior. − Chemical modifications that include multiple dopants and mixing of different perovskites in a solid solution , are the most effective approaches to design high-performance RFEs. However, the existence of phase segregation and the formation of undesired impurity phases are significant disadvantages associated with a large number of chemical dopants and the mixing of multiple perovskites. − With the complexity of the single-phase stabilization in multi-cation-doped RFE crystals, synthesizing single-phase perovskites crystals with a large number of different cations on the B -site would be an interesting approach toward designing high-performance RFEs for piezoelectric, pyroelectric, and electrocaloric applications.…”