Influence of titanium and oxygen vacancies on the transport and conducting properties of barium titanate

The transport and conducting properties of oxygen and titanium deficient cubic barium titanate (BT) were studied using atomistic simulations. The thermal expansion coefficient is shown to decrease when the number of titanium and oxygen vacancies increases. The influence of point defect concentration on the diffusion and conduction activation energies is determined, and the values are in good agreement with available experimental results. We also considered the defect energetics for formation of Ti and O vacancies using two proven interatomic potential models. Lattice static simulations reveal that strong binding energies exist for the trimer defect arrangement of VO-VTi-VO, and that they are similar to the formation enthalpy of rutile TiO2, implying that a strong driving force for the formation of this cluster defect is present. The results reported here can provide some helpful guidelines for optimization of the properties and functionalities of BT based on titanium and oxygen vacancies

Influence of titanium and oxygen vacancies on the transport and conducting properties of barium titanate

© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. The transport and conducting properties of oxygen and titanium deficient cubic barium titanate (BT) were studied using atomistic simulations. The thermal expansion coefficient is shown to decrease when the number of titanium and oxygen vacancies increases. The influence of point defect concentration on the diffusion and conduction activation energies is determined, and the values are in good agreement with available experimental results. We also considered the defect energetics for formation of Ti and O vacancies using two proven interatomic potential models. Lattice static simulations reveal that strong binding energies exist for the trimer defect arrangement of VO-VTi-VO, and that they are similar to the formation enthalpy of rutile TiO2, implying that a strong driving force for the formation of this cluster defect is present. The results reported here can provide some helpful guidelines for optimization of the properties and functionalities of BT based on titanium and oxygen vacancies.status: publishe

Obtention of Li3xLa2/3−xTiO3 ceramics from amorphous nanopowders by spark plasma sintering

In this work, LiLaTiO powder with nominal lithium content (x = 0.08) was synthesized by mechano synthesis method. Spark plasma sintering (SPS) was employed to prepare lithium lanthanum titanium oxide solid-state ceramic. The techniques of X-ray diffraction, high resolution scanning electron microscopy, and Raman spectroscopy were used to characterize the composition and microstructure of samples. The results showed that fine-grained ceramics with relative density of 95.5% were obtained by sintering the oxide powders at 1100°C for only 5 min.The authors would like to thank CNPq and FAPEAM Brazilian agencies for financial support n° [350405/2012–3]. Y. Romaguera-Barcelay also thanks the operation program ON.2 for their financial support (NORTE-07-0124-FEDER-000070 – Multifunctional nanomaterials)

Electrical response of La2/3-xLi3xTiO3 ceramics obtained by spark plasma sintering

The ceramic system La2/3-xLi3xTiO3 presents as an interesting candidate to be used as an electrolyte in solid-state Li-ion batteries. In this paper the electrical response of the ceramic, La2/3-xLi3xTiO3 with x = 0.11 is reported. La2/3-xLi3xTiO3 nanoparticles were synthesized by high energy milling and sintered by Spark Plasma Sintering from an amorphous phase. After sintering, the samples were structurally characterized by XRD and Raman techniques. Measurements of complex impedance varying frequency from 1 Hz to 10 MHz and temperature from 25 °C to 270 °C were performed. The study of DC conductivity allowed us to find the contributions to the total conductivity, grain, and grain boundary of the samples. From the activation energy values, it was possible to determine the conductive mechanism corresponding to the mobility of Li+ ions

Electrical response of La

The ceramic system La2/3-xLi3xTiO3 presents as an interesting candidate to be used as an electrolyte in solid-state Li-ion batteries. In this paper the electrical response of the ceramic, La2/3-xLi3xTiO3 with x = 0.11 is reported. La2/3-xLi3xTiO3 nanoparticles were synthesized by high energy milling and sintered by Spark Plasma Sintering from an amorphous phase. After sintering, the samples were structurally characterized by XRD and Raman techniques. Measurements of complex impedance varying frequency from 1 Hz to 10 MHz and temperature from 25 °C to 270 °C were performed. The study of DC conductivity allowed us to find the contributions to the total conductivity, grain, and grain boundary of the samples. From the activation energy values, it was possible to determine the conductive mechanism corresponding to the mobility of Li+ ions