Barium titanate tin oxides BaTi<sub>0.9</sub>Sn<sub>0.1</sub>O<sub>3</sub> referred to as (BTSO) doped with 0.5Er<sup>3+</sup> and co-doped with (0.75 and 1) Yb<sup&g...Barium titanate tin oxides BaTi<sub>0.9</sub>Sn<sub>0.1</sub>O<sub>3</sub> referred to as (BTSO) doped with 0.5Er<sup>3+</sup> and co-doped with (0.75 and 1) Yb<sup>3+</sup> ions, were prepared using a modified sol-gel method and calcinated at 1050<span style="white-space:nowrap;">?</span>C in the air for 4 h. The influence of the selected rare earth element on the structure morphology, dielectric properties behavior was investigated. From TEM micrographs, it has appeared that the particles have a spherical shape with a small size in nanoscale. The average particle size is determined both by TEM and XRD diffraction was found to be in agreement and within the range between 45.9 and 57.7 nm. The effects of Lanthanide incorporation on the evolution of these nano-crystalline structures were followed by XRD and (FTIR). The XRD patterns give rise to a single perovskite phase, while the tetragonality was found to decrease gradually with Er<sup>3+</sup> and Er<sup>3+</sup>/Yb<sup>3+</sup> ions, respectively. FTIR results showed enhancement of the crystallinity and the absence of carbonates upon increasing Yb<sup>3+</sup> ions concentration from 0.75 up to 1 mol%. The dielectric and conductivity properties were found to be enhanced by the nature and the concentration of the lanthanide element (Er<sup>3+</sup>, Yb<sup>3+</sup>) in the BTSO host lattice. The Curie temperature (T<sub>c</sub>) shifted to a lower value from 117 for BTSO: 0.5Er to 93 for BTSO: 0.5Er/1Yb and the permittivity <em>ε’</em> increased from 3972 to 6071, so BTSO: 0.5Er/1Yb good crystalline material candidate for capacitors application due to its higher permittivity.展开更多
Ba0.85Ca0.15Zr0.10Ti0.90O3(BCZT)lead-free ceramics demonstrated excellent dielectric,ferroelectric,and piezoelectric properties at the morphotropic phase boundary(MPB).So far,to study the effect of morphological chang...Ba0.85Ca0.15Zr0.10Ti0.90O3(BCZT)lead-free ceramics demonstrated excellent dielectric,ferroelectric,and piezoelectric properties at the morphotropic phase boundary(MPB).So far,to study the effect of morphological changes on dielectric and ferroelectric properties in lead-free BCZT ceramics,researchers have mostly focused on the influence of spherical grain shape change.In this study,BCZT ceramics with rod-like grains and aspect ratio of about 10 were synthesized by surfactant-assisted solvothermal route.X-ray diffraction(XRD)and selected area electron diffraction(SAED)performed at room temperature confirm the crystallization of pure perovskite with tetragonal symmetry.Scanning electron microscopy(SEM)image showed that BCZT ceramics have kept the 1D rod-like grains with an average aspect ratio of about 4.Rod-like BCZT ceramics exhibit enhanced dielectric ferroelectric(εr=11,906,tanδ=0.014,Pr=6.01μC/cm^2,and Ec=2.46 kV/cm),and electrocaloric properties(ΔT=0.492 K andz=0.289(K×mm)/kV at 17 kV/cm)with respect to spherical BCZT ceramics.Therefore,rod-like BCZT lead-free ceramics have good potential to be used in solid-state refrigeration technology.展开更多
The eco-responsible lead-free piezoelectric ceramics have been intensively searched for more than adecade, however, the final goal to replace toxic ceramics like lead zirconate titanate (PZT) with lead-freecompounds, ...The eco-responsible lead-free piezoelectric ceramics have been intensively searched for more than adecade, however, the final goal to replace toxic ceramics like lead zirconate titanate (PZT) with lead-freecompounds, having comparable or even better performance has not yet been reached. In this road, thelead-free ceramics Ba_(0.85)Ca_(0.15)Zr_(0.1)Ti_(0.9)O_(3) (BCZT), possessing excellent dielectric, ferroelectric, andpiezoelectric properties are regarded as serious candidates for the PZT replacement. Besides, nano-structuring BCZT is of paramount importance to enhance these functionalities even more. Here, BCZTmultipodes are designed by template-growth hydrothermal synthesis using hydrogen zirconate titanatenanowires. We demonstrate that the fabricated BCZT multipodes exhibit high dielectric permittivity of5300 with a temperature stability coefficient of ±5.9% between 20 and 140℃. A significant recoveredenergy density of 315.0 mJ/cm^(3) with high thermal stability and high energy storage efficiency of 87.4%,and enhanced large-signal piezoelectric coefficient d^(*)_(33) (310 pm/V) are found. Compared to the tradi-tional BCZT ceramics reported in the literature, relying on high-temperature processing, our sampleexhibits boosted energy storage parameters at a much lower temperature. These outcomes may offer anew strategy to tailor eco-responsible relaxor ferroelectrics toward superior energy storage performancefor ceramic capacitor applications.展开更多
Na_(0.5)(Bi_(3/4)RE_(1/4))_(0.5)TiO_(3)(RENBT,RE=Nd,Gd,Dy,and Ho)compounds were investigated in the framework of first-principles calculations using the full potential linearized augmented plane wave(FP-LAPW)method ba...Na_(0.5)(Bi_(3/4)RE_(1/4))_(0.5)TiO_(3)(RENBT,RE=Nd,Gd,Dy,and Ho)compounds were investigated in the framework of first-principles calculations using the full potential linearized augmented plane wave(FP-LAPW)method based on the spin-polarized density functional theory implemented in the WIEN2k code.Combined charge density distribution and Ti K-edge X-ray absorption spectra reveal that the RENBT compositions with high polarization values are accompanied by a higher TiO_(6)distortion,DyNBT,and NdNBT compounds.The effect of the rare-earth elements on the polarization is confirmed experimentally with the collection of the hysteresis loops.The investigation of the electronic properties of the compounds highlights the emergence of a magnetization owing to the 4f orbital effect of the rare-earth elements.Besides,the investigation of the chemical ordering shows a short-range chemical ordering for the pure composition and an increased A-site disorder for dysprosium doped NBT system.The increased disorder may speak for increased relaxor properties in the RE doped compositions.展开更多
文摘Barium titanate tin oxides BaTi<sub>0.9</sub>Sn<sub>0.1</sub>O<sub>3</sub> referred to as (BTSO) doped with 0.5Er<sup>3+</sup> and co-doped with (0.75 and 1) Yb<sup>3+</sup> ions, were prepared using a modified sol-gel method and calcinated at 1050<span style="white-space:nowrap;">?</span>C in the air for 4 h. The influence of the selected rare earth element on the structure morphology, dielectric properties behavior was investigated. From TEM micrographs, it has appeared that the particles have a spherical shape with a small size in nanoscale. The average particle size is determined both by TEM and XRD diffraction was found to be in agreement and within the range between 45.9 and 57.7 nm. The effects of Lanthanide incorporation on the evolution of these nano-crystalline structures were followed by XRD and (FTIR). The XRD patterns give rise to a single perovskite phase, while the tetragonality was found to decrease gradually with Er<sup>3+</sup> and Er<sup>3+</sup>/Yb<sup>3+</sup> ions, respectively. FTIR results showed enhancement of the crystallinity and the absence of carbonates upon increasing Yb<sup>3+</sup> ions concentration from 0.75 up to 1 mol%. The dielectric and conductivity properties were found to be enhanced by the nature and the concentration of the lanthanide element (Er<sup>3+</sup>, Yb<sup>3+</sup>) in the BTSO host lattice. The Curie temperature (T<sub>c</sub>) shifted to a lower value from 117 for BTSO: 0.5Er to 93 for BTSO: 0.5Er/1Yb and the permittivity <em>ε’</em> increased from 3972 to 6071, so BTSO: 0.5Er/1Yb good crystalline material candidate for capacitors application due to its higher permittivity.
基金The authors gratefully acknowledge the generous financial support of CNRST Priority Program(PPR 15/2015)Slovenian Research Agency Program(P1-0125)European Union’s Horizon 2020 Research and Innovation Program under the Marie Skłodowska-Curie Grant Agreement(No.778072).
文摘Ba0.85Ca0.15Zr0.10Ti0.90O3(BCZT)lead-free ceramics demonstrated excellent dielectric,ferroelectric,and piezoelectric properties at the morphotropic phase boundary(MPB).So far,to study the effect of morphological changes on dielectric and ferroelectric properties in lead-free BCZT ceramics,researchers have mostly focused on the influence of spherical grain shape change.In this study,BCZT ceramics with rod-like grains and aspect ratio of about 10 were synthesized by surfactant-assisted solvothermal route.X-ray diffraction(XRD)and selected area electron diffraction(SAED)performed at room temperature confirm the crystallization of pure perovskite with tetragonal symmetry.Scanning electron microscopy(SEM)image showed that BCZT ceramics have kept the 1D rod-like grains with an average aspect ratio of about 4.Rod-like BCZT ceramics exhibit enhanced dielectric ferroelectric(εr=11,906,tanδ=0.014,Pr=6.01μC/cm^2,and Ec=2.46 kV/cm),and electrocaloric properties(ΔT=0.492 K andz=0.289(K×mm)/kV at 17 kV/cm)with respect to spherical BCZT ceramics.Therefore,rod-like BCZT lead-free ceramics have good potential to be used in solid-state refrigeration technology.
基金The authors gratefully acknowledge the generous financial support of the European Union Horizon 2020 Research and Inno-vation actions MSCA-RISE-ENGIMA(No.778072)MSCA-RISE-MELON(No.872631)Z.K.,B.R.,D.V.,and M.S.acknowledge the Slovenian Research Agency program P1-0125 and P2-0091.
文摘The eco-responsible lead-free piezoelectric ceramics have been intensively searched for more than adecade, however, the final goal to replace toxic ceramics like lead zirconate titanate (PZT) with lead-freecompounds, having comparable or even better performance has not yet been reached. In this road, thelead-free ceramics Ba_(0.85)Ca_(0.15)Zr_(0.1)Ti_(0.9)O_(3) (BCZT), possessing excellent dielectric, ferroelectric, andpiezoelectric properties are regarded as serious candidates for the PZT replacement. Besides, nano-structuring BCZT is of paramount importance to enhance these functionalities even more. Here, BCZTmultipodes are designed by template-growth hydrothermal synthesis using hydrogen zirconate titanatenanowires. We demonstrate that the fabricated BCZT multipodes exhibit high dielectric permittivity of5300 with a temperature stability coefficient of ±5.9% between 20 and 140℃. A significant recoveredenergy density of 315.0 mJ/cm^(3) with high thermal stability and high energy storage efficiency of 87.4%,and enhanced large-signal piezoelectric coefficient d^(*)_(33) (310 pm/V) are found. Compared to the tradi-tional BCZT ceramics reported in the literature, relying on high-temperature processing, our sampleexhibits boosted energy storage parameters at a much lower temperature. These outcomes may offer anew strategy to tailor eco-responsible relaxor ferroelectrics toward superior energy storage performancefor ceramic capacitor applications.
基金Project supported by the Haute France Region/FEDER(project MASEN)H2020-RISE-ENGIMA-778072 project。
文摘Na_(0.5)(Bi_(3/4)RE_(1/4))_(0.5)TiO_(3)(RENBT,RE=Nd,Gd,Dy,and Ho)compounds were investigated in the framework of first-principles calculations using the full potential linearized augmented plane wave(FP-LAPW)method based on the spin-polarized density functional theory implemented in the WIEN2k code.Combined charge density distribution and Ti K-edge X-ray absorption spectra reveal that the RENBT compositions with high polarization values are accompanied by a higher TiO_(6)distortion,DyNBT,and NdNBT compounds.The effect of the rare-earth elements on the polarization is confirmed experimentally with the collection of the hysteresis loops.The investigation of the electronic properties of the compounds highlights the emergence of a magnetization owing to the 4f orbital effect of the rare-earth elements.Besides,the investigation of the chemical ordering shows a short-range chemical ordering for the pure composition and an increased A-site disorder for dysprosium doped NBT system.The increased disorder may speak for increased relaxor properties in the RE doped compositions.