scholarly journals Studies on Nano Crystalline Ceramic Superconductor LaZrYBaCa<sub>2</sub>Cu<sub>3</sub>O<sub>11</sub> at Three Different Temperatures

2014 ◽  
Vol 04 (02) ◽  
pp. 126-133
Author(s):  
Anitha S. Nair ◽  
Vinila V. S. ◽  
Sheelakumari Issac ◽  
Reenu Jacob ◽  
Anusha Mony ◽  
...  
2014 ◽  
Vol 03 (01) ◽  
pp. 1-9 ◽  
Author(s):  
V. S. Vinila ◽  
Reenu Jacob ◽  
Anusha Mony ◽  
Harikrishnan G. Nair ◽  
Sheelakumari Issac ◽  
...  

2012 ◽  
Vol 05 ◽  
pp. 472-479
Author(s):  
M. Hajfathalian ◽  
Z. A. Nemati ◽  
H. R. Madaah Hosseini

BaTiO 3-based solid solutions involve high piezoelectric and ferroelectric properties. One of the most favorable systems of this material is Ba ( Zr x Ti 1- x ) O 3. While nano structured ceramics of which have a great potential for using them in capacitors, actuators, transducers and dielectrics to reach high K values. In this study, nano crystalline Ba ( Zr x Ti 1- x ) O 3( x =0.1-0.8) which is called BZT composite has been prepared by mechanical alloying. The parameters affecting the process and properties were evaluated. The starting powders that are used here were nano sized high pure ZrO 2; submicron sized high pure TiO 2 and BaCO 3. The prepared powder was calcined, compacted and sintered at different temperatures and in various times. The structural changes and phase developments during mechanical alloying were studied by X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM) and Transition Electron Microscopy (TEM). The results showed that by using mechanical alloying method, high dense nano crystalline BZT ceramics were obtained successfully at very low sintering temperature. The dielectric constant of BZT was much great, because of using nano materials in this method at the temperatures of 1250-1400°C. The effect of high energy milling in micro structural development of nano crystalline BZT has been discussed as well as dielectric properties.


2012 ◽  
Vol 510-511 ◽  
pp. 454-460 ◽  
Author(s):  
H. Nawaz ◽  
S. Aftab ◽  
M. Shoaib ◽  
M. Siddiq

Phase pure Strontium doped PZT (Pb0.96Sr0.04Zr0.53Ti0.47O3) was synthesized by sol gel process. Zirconium and Titanium alkoxides were used as starting materials and Lead (II) Acetate trihydrate was used as Pb source. The alkoxides mixture was stabilized by acetylacetonate. The vacuum dried gel was calcined at different temperatures to study the calcination temperature and the resulting samples were analyzed by DSC, TG and XRD. The powder remained amorphous until a temperature of 550°C. The morphology and composition of the powder was studied using EDX, stereomicroscope and high resolution SEM.


2007 ◽  
Vol 121-123 ◽  
pp. 53-56 ◽  
Author(s):  
J. Azadmanjiri ◽  
Hojjatollah K. Salehani ◽  
A. Dehghan Hamedan ◽  
M. Sadeghi

In this work, high purity BaTiO3 (BT) nano-powders by a sol-gel process was prepared with Ba(NO3)2 and Ti(C4H9O)4 materials in order to acquire uniform size grains. The effects of the crystallinity, microstructure of BT nano-powders calcined at different temperatures and dielectric properties of the ceramics were investigated by XRD, SEM and impedance analyzer, respectively. Scanning electron microscopy and X-ray diffraction investigation revealed cubic plates and crystallite size. The results revealed that crystallite size and calcination temperature of BT and influence on the dielectric constant.


2015 ◽  
Vol 7 (1) ◽  
pp. 1352-1358
Author(s):  
Jayakumari Isac ◽  
Anusha Mony ◽  
Harikrishnan G. Nair ◽  
Reenu Jacob ◽  
Sheelakumari Issac ◽  
...  

The nano-sized ceramic superconducting material YSBCO having  perovskite structure was prepared according to the chemical formula by the thermo chemical solid state reaction technique using a high-energy ball milling process through mechanically assisted synthesis. It was characterized by XRD, SEM and EDX. Here the authours studied the thermal characterization  using  TGA, DTA and DSC.


2002 ◽  
Vol 737 ◽  
Author(s):  
C. Rozo ◽  
L. F. Fonseca ◽  
O. Resto ◽  
S. Z. Weisz

ABSTRACTSi-rich SiO2, Nd-doped Si-rich SiO2 and Nd-doped SiO2 thin films were prepared. Photoluminescence (PL) spectra for visible and infrared were obtained for each as-deposited film. The samples were annealed by steps to different temperatures within the range 600°C-1100°C for 30 minutes at each annealing temperature. PL spectra were obtained at each step and their characteristics were studied. The best annealing temperature for the PL of the rare earth (RE) ions was obtained. The PL spectra of the films were compared with one another. Energy transfer from the silicon nanocrystals (Si nc) to the RE ions is verified using excitation wavelength and excitation power spectra.


2015 ◽  
Vol 22 (1) ◽  
pp. 105-112 ◽  
Author(s):  
Yuanpeng Zhang ◽  
Ali Karatutlu ◽  
Osman Ersoy ◽  
William Little ◽  
Giannantonio Cibin ◽  
...  

The structure of small (2–5 nm) Ge quantum dots prepared by the colloidal synthesis route is examined. Samples were synthesized using either GeO2or GeCl4as precursor. As-prepared samples were further annealed under Ar or H2/Ar atmosphere at different temperatures in order to understand the effect of annealing on their structure. It was found that as-prepared samples possess distinctly different structures depending on their synthesis route as indicated by their long-range ordering. An appreciable amount of oxygen was found to be bound to Ge in samples prepared with GeO2as a precursor; however, not for GeCl4. Based on combined transmission electron microscope, Raman, X-ray diffraction and X-ray absorption measurements, it is suggested that as-prepared samples are best described by the core-shell model with a small nano-crystalline core and an amorphous outer layer terminated either with oxygen or hydrogen depending on the synthesis route. Annealing in an H2Ar atmosphere leads to sample crystallization and further nanoparticle growth, while at the same time reducing the Ge—O bonding. X-ray diffraction measurements for as-prepared and annealed samples indicate that diamond-type and metastable phases are present.


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