- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
[IEEE 2018 IEEE ISAF-FMA-AMF-AMEC-PFM Joint Conference (IFAAP) - Hiroshima (2018.5.27-2018.6.1)] 2018 IEEE ISAF-FMA-AMF-AMEC-PFM Joint Conference (IFAAP) - Data-Mining Driven Design for Novel Perovskite-type Piezoceramics
摘要： Materials Genome Initiative is envisioning the discovery, development, manufacturing and deployment of advanced materials twice as fast and at a fraction of cost. High throughput computation and experimentation will generate big data, which underscores the emergence of the fourth paradigm---data science. In contrast to machine-learning needing big-data, data-mining assisted by domain knowledge and expertise works well with a limited number of data. In this presentation, data-mining based on material genome approach were performed in field of perovskite-type oxides. New ferroelectric ceramics based on BiFeO3 for high temperature piezoelectric applications are realized with piezoresponse of 1.5~4.0 times the present commercial non-perovskite counterpart. Our essay demonstrates data-mining driven searching sure able to reduce time-to-insight and human effort on synthesization, accelerating new materials discovery and deployment.
关键词： piezoceramics,perovskite-type oxides,material genome approach,high Curie temperature,data-mining
更新于2025-09-23 15:23:52
-
Improved upconversion photoluminescence properties of 0.965K0.4Na0.58Li0.02Nb0.96Sb0.04O3–0.035Bi0.5K0.5ZrO3:0.25%Er/xIn lead-free piezoelectric ceramics with balanced piezoelectric coefficient and Curie temperature
摘要： A series of erbium- and indium-doped 0.965K0.40Na0.58Li0.02Nb0.96Sb0.04O3–0.035Bi0.5K0.5ZrO3:0.25%Er/xIn lead-free piezoelectric ceramics with upconversion photoluminescence (UCPL) properties were prepared by the conventional solid state reaction. A systematical investigation into the effects of In3+ doping on the structural, dielectric, ferroelectric, piezoelectric, and UCPL properties of the ceramics was carried out. The distribution of Er3+-sites could be modified by In3+ doping according to the analysis of UV–Vis-NIR absorption cross-section, resulting in improved piezoelectric and photoluminescence properties of the ceramics. The optimized comprehensive properties are performed by the x = 0.25% samples of which the piezoelectric coefficient d33 ~ 257 pC/N, Curie temperature TC ~ 273 °C, remanent polarization Pr ~ 12.5 μC/cm2, dielectric constant εr ~ 1551, and d33 ~ 257 pC/N which is the supreme piezoelectric coefficient achieved in KNN-based UCPL ceramics as of now. The results demonstrate that erbium and indium co-doped KNN-based ceramics may have potential applications in electro-optical devices.
关键词： Upconversion photoluminescence,Erbium and indium co-doping,Piezoelectric coefficient,Lead-free piezoelectric ceramics,Curie temperature
更新于2025-09-23 15:21:01
-
Ferroelectric mesocrystalline BaTiO <sub/>3</sub> /BaBi <sub/>4</sub> Ti <sub/>4</sub> O <sub/>15</sub> nanocomposite: formation mechanism, nanostructure, and anomalous ferroelectric response
摘要： Ferroelectric mesocrystalline nanocomposites are promising materials for the enhancement of ferroelectricity via lattice strain engineering due to their high density of heteroepitaxial interfaces. In the present study, a ferroelectric mesocrystalline BaTiO3/BaBi4Ti4O15 (BT/BBT) nanocomposite was synthesized using the layered titanate H1.07Ti1.73O4 via a facile two-step topochemical process. The BT/BBT nanocomposite is constructed from well-aligned BT and BBT nanocrystals oriented along the [110] and [11?1] crystal-axis directions, respectively. Lattice strain is introduced into the nanocomposite through the formation of a BT/BBT heteroepitaxial interface, which results in a greatly elevated Curie temperature for BBT in the range of 400 °C to 700 °C and an improved piezoelectric response with d*33 = 130 pm V?1. In addition, the BT/BBT nanocomposite is stable up to a high temperature of 1100 °C; therefore, mesocrystalline ceramics can be fabricated as high-performance ferroelectric materials.
关键词： piezoelectric response,nanocomposite,ferroelectric,mesocrystalline,BaBi4Ti4O15,BaTiO3,Curie temperature,lattice strain
更新于2025-09-19 17:15:36
-
Enhanced piezoelectric properties of Sr <sub/>(1.7)</sub> (Na <sub/>0.5</sub> Bi <sub/>0.5</sub> ) <sub/>0.3</sub> Bi <sub/>4</sub> Ti <sub/>5</sub> O <sub/>18</sub> ceramics in the system Sr <sub/> (2- <i>x</i> ) </sub> (Na <sub/>0.5</sub> Bi <sub/>0.5</sub> ) <sub/><i>x</i> </sub> Bi <sub/>4</sub> Ti <sub/>5</sub> O <sub/>18</sub> (where 0 ≤ <i>x</i> ≤ 0.5)
摘要： Fine powders synthesized via sol-gel route were employed to fabricate Sr(2-x)(Na0.5Bi0.5)xBi4Ti5O18 (SNBT, where x = 0, 0.1, 0.25, 0.3, 0.4 and 0.5) ceramics. The composition (x) dependent structural changes associated with SNBT ceramics were analyzed using X-ray powder diffraction (XRD), transmission electron microscopy (TEM) and Raman spectroscopic techniques. Average grain size analyses carried out on the SNBT ceramics by scanning electron microscopy revealed an important role played by the dopants in inhibiting the grain growth. Dielectric constants and the Curie temperature of the ceramics were found to decrease and increase respectively with increase in x. The increase in Curie temperature with increase in x was attributed to the decrease in the tolerance factor. The specific composition (x = 0.3) of the SNBT ceramics exhibited improved piezo and ferroelectric properties associated with a higher Curie-temperature (569 K). The piezoelectric coefficient (d33) and the planar electromechanical coupling coefficient (kp) of SNBT(x = 0.3) were enhanced by 25% and 42% respectively as compared to the undoped ceramics.
关键词： Curie temperature,Ferroelectrics,Piezoelectric constant,Tolerance factor
更新于2025-09-10 09:29:36
-
Raising the Operating Temperature of (Ga,Mn)As/GaAs Spin Light Emitting Diodes by Applying Post-Growth Treatment
摘要： Spin light emitting diodes (spin-LEDs) containing (Ga,Mn)As ferromagnetic layers are fabricated based on InGaAs/GaAs heterostructures and studied. We achieve increases in the operating temperatures of our spin-LEDs by subjecting the surface of the structures, prior to depositing an ohmic metal contact, to pulsed laser annealing. The fabricated devices produce circularly polarized electroluminescence when placed in an external magnetic field. The temperatures at which circularly polarized electroluminescence is still observed is raised from 30 K for unprocessed structure to 110 K for laser-annealed structures. The observed effect is linked to an increase in the Curie temperature of the (Ga,Mn)As layer as a result of laser impact.
关键词： ferromagnetic layers,circularly polarized electroluminescence,Curie temperature,Mn)As,pulsed laser annealing,Spin light emitting diodes,(Ga
更新于2025-09-10 09:29:36
-
High Ferroelectricities and High Curie Temperature of BiInO <sub/>3</sub> PbTiO <sub/>3</sub> Thin Films Deposited by RF Magnetron Sputtering Method
摘要： Properties of ferroelectric ??BiInO3-(1 ? ??)PbTiO3 (??BI-(1 ? ??)PT) thin films deposited on (101) SrRuO3/(200) Pt/(200) MgO substrates by rf magnetron sputtering method and effects of deposition conditions are investigated. The structures of the ??BI-(1???)PT films are characterized by x-ray diffraction and scanning electron microscopy. The results indicate that the thin films are grown with mainly (001) orientation. The chemical compositions of the films are analyzed by scanning electron probe and the results indicate that the loss phenomena of Pb and Bi elements depend on the pressure and temperature during the sputtering process. The sputtering parameters including target composition, substrate temperature, and gas pressure are adjusted to obtain optimum sputtering conditions. To decrease leakage currents, 2 mol% La2O3 is doped in the targets. The ?? –?? hysteresis loops show that the optimized ??BI-(1 ? ??)PT (?? = 0.24) film has high ferroelectricities with remnant polarization 2??r = 80 ??C/cm2 and coercive electric field 2??c = 300 kV/cm. The Curie temperature is about 640°C. The results show that the films have optimum performance and will have wide applications.
关键词： ferroelectric,rf magnetron sputtering,BiInO3-PbTiO3,thin films,Curie temperature
更新于2025-09-09 09:28:46
-
Atomic ordering, magnetic properties, and electronic structure of Mn<sub>2</sub>CoGa Heusler alloy
摘要： The magnetic properties and atomic arrangement of Mn2CoGa Heusler alloy were investigated experimentally and by theoretical calculations. The magnetic moment derived from spontaneous magnetization at 5 K was 2.06 μB/f.u. and was close to the integer number of the expected value from theoretical calculation and the Slater–Pauling rule predicted by Galanakis et al. The Curie temperature and L21-B2 order-disorder phase transition temperature were 741 and 1047 K, respectively. Powder neutron diffraction experiment results suggested that the atomic arrangement prefers an L21b-type structure rather than that of Hg2CuTi, being consistent with our previous results of high-angle annular dark-field-scanning transmission electron microscopic observations. The magnetic moments obtained were in good agreement with the theoretical values in the model of the L21b-type structure. The density of states obtained by the first-principles calculation combined with the coherent potential approximation in Mn2CoGa with the L21b-type crystal structure maintained the half-metallic character, even though disordering by Mn and Co atoms was introduced.
关键词： powder neutron diffraction,magnetic moment,Half-metal-type ferromagnets,order-disorder phase transition,atomic ordering,Curie temperature
更新于2025-09-09 09:28:46
-
Preparation and Characterization of Ba1-xSrxTiO3 by Sol-Gel Method
摘要： Barium strontium titanate (BST) with formula (Ba1-xSrxTiO3) has been synthesized by sol-gel method with different stoichiometric compositions (x = 0.3, 0.4, 0.5, 0.6). The raw materials which used to prepare compounds are (Ba,Sr) acetate as a source (Ba,Sr) and titanate isopropoxide source. The FE-SEM images showed that the particles size reduced from 464 to 13 nm when strontium concentration increased from 0.3 to 0.6. The X-ray diffraction studies have confirmed that Ba0.7Sr0.3TiO3 sample have the tetragonal phase while remaining samples have a cubic phase. The intensity of the major peaks were decreased and shifted toward higher 2θ angles when Sr2+ ions increases.
关键词： Barium strontium titanate,Curie Temperature,Ferroelectric materials,Perovskite structure
更新于2025-09-04 15:30:14
-
Abnormal Curie-temperature shift in Ho-doped BaTiO3 ceramics with the self-compensation mode
摘要： Nominal (Ba1?xHox)(Ti1?xHox)O3 ceramics (BHTH) were prepared at 1400 °C using a mixed-oxides method. The structure, microstructure, dielectric properties, and point defects of BHTH were investigated using X-ray di?raction (XRD), scanning electron microscopy (SEM), photoluminescence (PL) spectroscopy, electron paramagnetic resonance (EPR), and dielectric measurements. Ho3+ in BaTiO3 prefers a self-compensation mode with a slight Ba-site preference, and the solubility limit of Ho3+ in the ?ne-grained BHTH (0.5 μm) was determined by XRD to be x = 0.03. An abnormal phenomenon was observed: the Curie temperature of BHTH shifted towards high temperatures from 128 °C at x = 0.01 to 131 °C at x = 0.03. Ho3+ is inferred to be a potential codopant to achieve X8R speci?cation when BaTiO3 is doped with Ho3+ and other types of ions.
关键词： Self-compensation mode,Point defects,Ho-doped BaTiO3,The Curie temperature,Dielectrics
更新于2025-09-04 15:30:14