Dielectric Constant Increase of Yttrium-Doped HfO2 by Structural Phase Modification

2004 ◽  
Author(s):  
Koji Kita ◽  
Kentaro Kyuno ◽  
Akira Toriumi
2003 ◽  
Vol 150 (12) ◽  
pp. F203 ◽  
Author(s):  
Daisuke Ryuzaki ◽  
Takeshi Ishida ◽  
Takeshi Furusawa

2011 ◽  
Vol 418-420 ◽  
pp. 721-725
Author(s):  
Yi Shan Wang ◽  
Xiang Yun Deng ◽  
Yan Jie Zhang ◽  
Ren Bo Yang ◽  
Li Ren Han ◽  
...  

The different concentration La2O3-doped BaTiO3 ceramics were prepared by sol-gel method. The ferroelectric and dielectric properties of the ceramics are characterized by TF analyzer 2000. With the increased amount of La2O3-doped, the dielectric constant increase gradually, when the sintering temperature is 1250 °C, the dielectric constant has reached 4648 for La2O3 with 0.4%-doped. With the temperature increased the dielectric constant of La-BaTiO3 increase gradually, when the sintering temperature is 1290 °C, the dielectric constant has reached 7066 for La2O3 with 0.4%-doped.


2012 ◽  
Vol 48 (2) ◽  
pp. 215-217 ◽  
Author(s):  
Miguel Palomino ◽  
Avelino Corma ◽  
Jose L. Jordá ◽  
Fernando Rey ◽  
Susana Valencia

Author(s):  
Majeed Ali Habeeb ◽  
Ahmed Hamza Abbas

In the present work, Polypropylene (PP) was blended with poly methyl methacrylate (PMMA) to form (PP/PMMA) polymer blends. High Density Polyethylene (HDPE) was mixed into these blends at different weight fractions (2,4,6,8) % wt to form (PP/PMMA/HDPE) blends were prepared using an one screw extruder. results obtained from Scanning Electron Microscopy (SEM) revealed that there was a reduction in surface roughness any decrease in clusters, drilling and bends, as for Fourier Transform Infrared (FT-IR) spectrometry showed no change in the wave numbers of the functional groups. The optical properties of samples are investigated by measuring optical absorption spectra in the wavelength range from 260 to 1100 nm. this results show that Eg of the blends increases with increasing high density polyethylene contents, the indirect optical band gaps for (PP/PMMA) and (PP/PMMA/HDPE) blends were estimated to be about 2.83,2.9,2.95,3and 3.1 eV for indirect allowed transitions, whereas the indirect forbidden band gaps were determined as 2,2.1,2.15,2.2 and 2.3 eV with increase high density Polyethylene contents, respectively. The absorbance, absorption coefficient, extinction coefficient and the imaginary dielectric constant of (PP/PMMA/HDPE) decreases with increasing of HDPE percentages except the transmittance, refraction index and real part of the dielectric constant increase with increasing of high density polyethylene.


2017 ◽  
Vol 24 (6) ◽  
pp. 875-881
Author(s):  
Sigit Tri Wicaksono ◽  
Shih-Hsuan Chiu ◽  
Kun-Ting Chen ◽  
Sheng-Hong Pong

AbstractThe acrylate-based photopolymer consists of tetra-functional polyester acrylate (TPA), and hexanediol diacrylate (HDDA) has been successfully composited with nano barium titanate (BaTiO3) and completely cured via a digital light processor RP machine. The degradation temperature, tensile strength, hardness, resistivity, and dielectric constant of samples were characterized by Thermo Gravimetric Analyzer Hi-Res TGA2950, Universal Tensile Machine JIA701, Hardness Shore D tester, Fluke 117 multimeter, and Agilent B1500A Semiconductor Device Analyzer, respectively. The morphology changes of the samples were also investigated using the JEOL JSM-6390LV scanning electron microscopy (SEM). The results show that the improvement of degradation temperature is not obvious. Furthermore, the modulus elasticity, hardness, and dielectric constant increase as the filler loading increases up to 2 phr, but the resistivity is vice versa. Interestingly, there is an inverse correlation between dielectric constant and resistivity of photopolymer/BaTiO3 nanocomposite.


1996 ◽  
Vol 453 ◽  
Author(s):  
T. Nagai ◽  
M. Sugiyama ◽  
M. Sando ◽  
K. Niihara

AbstractA structural phase transformation from hexagonal to monoclinic has been found in an ordered perovskite compound (Ba, Sr)(Mg1/3Ta2/3)O3, (BSMT). The transformation temperature of BSMT increases and the dielectric constant also changes from 24 to 27 with an increase in Sr concentration. The temperature coefficient of the dielectric constant is also changed with the variation of Sr content. In order to apply BSMT for practical use of dielectric resonators these changes in the dielectric properties, which is dominated by the phase transformation, must be controlled. In order to clarify the relation between the dielectric constant change and the structural phase transformation, phonon mode of BSMT has been studied using Raman spectroscopy. Change in the Raman spectrum of BSMT is classified into four steps. The first and the fourth steps correspond to the phase transformation. The change in the phonon mode detected by Raman spectroscopy is discussed in connection with the structural change.


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