Results 1 - 10 of 15684
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[en] Highlights: • Dielectric constant vs temperature data are analyzed by multiple Gaussian peaks. • Samples show ferro-paraelectric and two magnetic order induced phase transitions. • The relaxation mechanisms exhibit a +ve frequency shift with increase in temperature. • Samples exhibit multiferroic characteristics with tunable M-E coefficient.
[en] Barium zirconate was prepared by liquid phase sintering at low temperatures and used as a substrate for a YBCO melt process. The liquid phase was provided by barium cuprate melt, barium peroxide melt or barium zirconate liquid (in case of plasma spraying). The infiltration resistance against the barium cuprate melt could be improved, but is not yet sufficient for application. (orig.)
[en] We present ab initio calculations of the longitudinal flexoelectricity for BaTiO3 and SrTiO3 using a direct approach. The calculated value for SrTiO3 agrees with recently reported measurements. For BaTiO3, however, the theoretical values are smaller than the measured ones; possible reasons for the discrepancy are discussed. (fast track communication)
[en] In BaxC60 superconductivity (sc) at Tc = (6.8±0.2) K is associated with the x=4 phase. Here the authors present pressure studies of Tc of a BaxC60 sample (dTc/dp= -1.9 K/GPa) which exhibits a large volume fraction of the x=4 phase. In the alkali-fullerides K3C60 and Rb3C60 Tc is governed by the electronic density of states N(EF) (Tc ∝exp-1/N(EF)V). The dependence of N(EF) on volume can be approximated by N(EF)=N0deff3 where deff is the surface to surface distance of neighboured C60-molecules. This relationship is corroborated by (Tc, d)-data of various compounds of the form A3-xBxC60 (A: K, Rb; B: K, Rb, Cs; x≤2). Strong deviation from this behavior is found for the alkaline-fulleride superconductor Ba4C60. This deviation is attributed to the hybridization of alkaline-metal s-, d-states and C60 π-states
[en] (Ce, Y) codoped BaZrO3 ceramics, BaZr0.1Ce0.7Y0.2O3-δ and BaZr0.4Ce0.4Y0.2O3-δ ceramics were synthesized via solution combustion based on the glycine nitrate process. The dielectric properties of the samples have been investigated in the temperature range from 300 to 1000 K and frequency range from 102 Hz to 106 Hz. It is observed that the samples exhibit colossal dielectric behavior in the temperature below ∼600 K. The colossal dielectric behavior is composed of two sets of relaxations with the low- and high-temperature relaxations being caused by the dipole pairs of -Y and -Y, respectively. In the temperature higher than ∼600 K, the samples show two dielectric anomalies with extremely large dielectric permittivity over 106. It is argued that the low-temperature dielectric anomaly is the typical pseudo-relaxor behavior caused by ion-hopping-motion. While the high-temperature dielectric anomaly results from the negative capacitance effect. (paper)