Structure and energy storage properties of Ti vacancies charge compensated Re 2O3-doped SrTiO3 (Re = Pr, Nd, Gd) ceramics

In this article, low dielectric loss pure or Mndoped BiFeO 3 -Bi(Zn 1/2 Ti 1/2 )O 3 -BaTiO 3 (BF-BZT-BT) lead-free piezoceramics with various compositions were prepared using a refined solid state reaction electroceramic processing. The rhombohedral-pseudocubic structural phase boundary was determined with powder X-ray diffraction method and found dependent on ceramic grain size, which shifts far away from the BF-rich corner with increasing microstructure grain size. In contrast to BF-BT binary system, low dielectric loss was understood by mechanism of reduction of oxygen vacancies with doping MnO 2 combined with stabilization of Bi-perovskite phase by adding BZT third member. Full piezoresponse of d 33 C 145 pC/N was obtained in the Mn-doped BF-xBZTyBT (0.01 \ x \ 0.05 and 0.27 B y B 0.31) coarsegrained ceramics near the structural phase boundary, in agreement with prediction by relationship of d 33 = ae 33 -be 33 2 . Ferroelectric polarization subswitching and related low piezoresponse observed in the BZT-riched ceramics were observed and argued extrinsically resulting from residual internal stresses. Primary experiments showed annealing and subsequent quenching treatment eliminate residual internal stresses and increase piezoresponse for the BZT-riched ceramics.

Section: Piezoelectric Propertiesmentioning

confidence: 66%

Section: Piezoelectric Propertiesmentioning

confidence: 92%

Structural phase boundary of BiFeO3–Bi(Zn1/2Ti1/2)O3–BaTiO3 lead-free ceramics and their piezoelectric properties

Lin

Zhang

Zheng

et al. 2015

“…Meanwhile, bismuth oxide usually evaporate during high temperature sintering so that the real concentration of A-site vacancies may be higher than the value calculated above [20,21]. Owing to electric-neutrality, the charge compensation mechanism causes correspondingly same concentration of oxygen vacancies in the BF-BZT-BT ceramics [38][39][40]. Therefore, the large dielectric losses observed in the undoped BF69.6-BZT1.4-BT29 ceramics can be reasonably attributed to dielectric relaxation caused by a large Our extensive studies showed that this dielectric relaxation caused by space charge was still occurring when BZT content was increased to 5 %, but completely suppressed when BZT content was 10 % for those BF-BZT-BT ceramics with BF content more than 60 %.…”

Section: Dielectric Propertiesmentioning

confidence: 92%

“…Analogously, there also lack consistent XRD and SEM microstructure data on the BF-BT ceramics. Nevertheless, extensive studies on perovskite oxides revealed that microstructure grain size can set strong influence on the crystallographic structure and related composition-structural phase boundary position, which has been observed to induce lattice structural phase transition from low-symmetry to high-symmetry in nanocrystalline BaTiO 3 and PbTiO 3 , or shifting of structural phase boundary position in fine-grained Pb(Zr,Ti)O 3 , 0.8Pb(Mg 1/3 Nb 2/3 )O 3 -0.2PbTiO 3 and BiFeO 3 -Bi(Zn 1/2 Ti 1/2 )O 3 -PbTiO 3 (BF-BZT-PT) ceramics [26,[38][39][40][41][42][43]. From viewpoint of relationship between lattice structure and microstructure grain size of ceramics, the 0.67BF-0.33BT is reasonably believed as the critical composition of the rhombohedral-pseudocubic structural phase boundary for the coarse-grained BF-BT ceramics, which will shift towards BF-riched corner with decreasing microstructure grain size [30].…”

Section: Structural Characterizationsmentioning

confidence: 99%

Stable piezoelectric property of modified BiFeO3–BaTiO3 lead-free piezoceramics

Lin

Zhang

2015

Perovskite-structured 0.696BiFeO 3 -0.014Bi(Zn 1/2 Ti 1/2 )O 3 -0.29BaTiO 3 (BF69.6-BZT1.4-BT29) lead-free piezoceramics with various MnO 2 addition were prepared using a refined solid state reaction electroceramic processing. Powder X-ray diffraction measurements showed their crystallographic structure being of rhombohedral structure and scanning electron microscopy observations revealed that MnO 2 -doping enhances ceramic microstructure grain size growth. In contrast to BF-BT ceramics, low dielectric loss ceramics were obtained with combined strategies of refined electroceramic processing, Mn-doping and adding BZT third member. A good combination of ferroelectric and piezoelectric property was obtained in the 0.22 and 0.26 % in weight MnO 2 -doped BF69.6-BZT1.4-BT29 coarse-grained ceramics and discussed in relation to microstructure grain size effect and point defect effect. Excellent time and thermal aging stabilities of piezoelectric constant d 33 were also experimentally demonstrated and argued resulting from the feature of higher ferroelectric Curie temperature (T C ) and no ferroelectric-ferroelectric structural phase transition below T C of BF-BZT-BT system.

“…In general, the energy density of a linear dielectric is defined as U = 0.5e 0 e r E 2 , where e 0 , e r , E are the permittivity of free space, the relative dielectric constant and the applied electric field, respectively. At present, much work [6,7] has been performed on SrTiO 3 -based dielectrics to increase the dielectric constant e r and/or dielectric strength. However, comprehensive breakdown characteristics of SrTiO 3 dielectric have not been reported earlier.…”

Section: Introductionmentioning

confidence: 99%

Dielectric breakdown characteristics of sol–gel derived SrTiO3 films

Peng

Yao

et al. 2016

Dielectric breakdown behavior of sol-gel derived SrTiO 3 films has been studied systematically. The dielectric strength and leakage characteristics of SrTiO 3 films were observed to have a strong dependence on the top electrode materials. Compared with films with Ti or Al electrode, SrTiO 3 films with Au electrode exhibited relatively low dielectric breakdown strength. Simultaneously, a broad area of damage occurred in the Au electrode after breakdown, which is closely related to the self-healing breakdown mechanism. The corresponding leakage current kept the same order of magnitude when the electric field was higher than 100 MV/m. The higher dielectric strength of the films with Ti or Al electrode is attributed to anodic oxidation of metal electrode.