High-temperature perovskite relaxor ferroelectrics: A comparative study

Abstract

The recent discovery of high-temperature piezoelectric ceramics based on Bi(Me′Me″)O3-PbTiO3 solutions have also permitted the development of high-temperature relaxor ferroelectrics with ternary solid solutions. One of the high-temperature compositions based on the xBiScO3-yPb(Mg1∕3Nb2∕3)O3-zPbTiO3 (xBS-yPMT-zPT) ternary system exhibited a high permittivity maxima of ∼17 000 and a Tmax of 500–550 K. These materials are compared to complex lead perovskite relaxor ferroelectrics by determination of the activation energy, EA, and freezing temperature, Tf, from the Vögel-Fulcher relationship and also a high-temperature deviation temperature, TD, from the Curie-Weiss behavior. It was found that these parameters scale within the perovskite relaxor systems and from the self-consistent trends of these defining parameters. It is suggested that a general comparison for relaxor ferroelectrics may exist. The highest EA, Tf, and TD values all exist within the xBS-yPMT-zPT ternary system within the relaxor ferroelectric systems compared in this study. Furthermore, given the compositional trends within these comparisons, insights into the nature of the dynamic polarization behavior in the perovskite relaxor ferroelectrics may be gained.

Microstructure and electrical properties of Aurivillius phase (CaBi2Nb2O9)1−x(BaBi2Nb2O9)x solid solution

“…18 But traditional RFE piezoelectrics, such as Pb͑Mg 1/3 Nb 2/3 ͒O 3 -PbTiO 3 and Pb͑Zn 1/3 Nb 2/3 ͒O 3 -PbTiO 3 , are not suitable for application under harsh thermal conditions due to their relatively low T m temperatures ͑Ͻ300°C͒, at which there is the maximum of dielectric permittivity. 19,20 There are relatively few reports on relaxor behavior in BLSFs solid solution ceramics. we reported that CBNO has the highest-known Curie point ͑943°C͒ among BLSFs and the highest thermal depoling temperature for polycrystalline ferroelectric ceramics.…”

Morphotropic phase boundary in (1-x)Bi(Sc0.5In0.5)O3-xPbTiO3 high temperature piezoelectric system

“…With C'~10 5 K, the high-temperature paraelectric phase above TB is driven by a soft optic mode condensation or a displacive transition, with C'~10 3 K, the transition would be more likely order-disorder. 15) Seen from Table 1, C' are in the order of ~10 5 K, consistent with a displacive phase transition. Simultaneously, the deviation Tc-T0 is above zero, indicative of first-order phase transition from a hightemperature paraelectric phase to a ferroelectric one.…”

Relaxor nature in lead-free Sr5LaTi3Nb7O30 tetragonal tungsten bronze ceramics

“…Temperature dependences of e 0 follow the Curie-Weiss (CW) law above $330 K for all the applied frequencies from 1 Hz to 10 MHz with the extrapolated critical temperature T CW % 146 K and the Curie-Weiss constant C $ 1.22 Â 10 5 K. The dielectric constant deviates from the CW law below 330 K, which is called the deviation temperature T D , 28,29 and indicates the diffuse behavior. The diffuse behavior of dielectric constant from T m to T D can be described by a modified Curie Weiss law 30,31 …”

“…13 In relaxor ferroelectrics, deviation of the e 0 (T) curve from the Curie-Weiss behavior at temperature above T m indicates the formation of polar nanoregions, and the deviation temperature T D is also determined as the Burn's temperature. 28 …”