Piezoelectric properties of SrBi 2 M 2− x V x O 9 (M = Nb and Ta) ceramics

Vanadium-substituted strontium bismuth tantalate, Sr 0.8 Bi 2.2 Ta 2− x V x O 9 (SBTV x ), and strontium bismuth niobate, SrBi 2 Nb 2− x V x O 9 (SBNV x ), ceramics were synthesized by a low-temperature processing, and their dielectric, ferroelectric and piezoelectric properties were characterized. With the partial substitution of tantalum or niobium by vanadium cations, the single phase of the ABi 2 M 2 O 9 -type structure was preserved and the sintering temperature was significantly decreased. For the SBNV ceramics, the T c of 437 ∘ C for x = 0.0, the vanadium content hardly changed. On the other hand, the T c of the SBTV ceramics increased from 408 ∘ C for the non-substituted SBTV to 414 ∘ C for x = 0.05 and then with the increasing vanadium content, the T c decreased to 379 ∘ C for x = 0.20. The remanent polarizations, P r , of SBTV and SBNV at room temperature were 4.9 and 5.4 μC/cm 2 , respectively. All the obtained independent electromechanical coupling factors of the SBTV0.05 ceramics were as follows: k p = 0.119, k 31 = 0.073, k 33 = 0.165, k 15 = 0.051 and k t = 0.134, and the SBNV0.05 ceramics were as follows: k p = 0.074, k 31 = 0.045, k 33 = 0.175, k 15 = 0.106 and k t = 0.140. These coupling factors were higher than those of the non-substituted materials. From these results, the vanadium-substituted SBT and SBN-based materials can be expected to be lead-free piezoelectric resonator materials that can be prepared at low sintering temperatures.