Impact of Silver Doping on the Crystalline Size and Intrinsic Strain of MPA-Capped CdTe Nanocrystals: A Study by Williamson–Hall Method and Size–Strain Plot Method

Silver doping into (Bi, Pb)2Sr2Ca2Cu3O10 superconducting composite tapes was found to accelerate the formation process of high-Tc (2223) phase owing to lowering the partial melting point of the samples. The differential thermal analysis (DTA) results showed that the partial melting temperature of the sample was lowered by about 10 °C from 850 °C to 840 °C by silver doping. However, with sufficient sintering both the silver-doped and undoped samples can reach a very high level of high-Tc phase fraction, suggesting that the silver doping only speeds up the rate of high-Tc phase formation, but does not change the final phase assemblage of the materials. The reaction kinetics was analyzed by using the Avrami equation, and the results indicated that the conversion process of low-Tc (2212) phase to high-Tc (2223) phase was a diffusion-controlled, two-dimensional reaction. The correlation of the phase evolution with electrical property inside the superconducting tape during the process of heat treatment was also discussed.

Download Full-text

Zn2+ addition: A facile way to obtain CdTe nanocrystals powders with enhanced fluorescence emission

Colloids and Surfaces A Physicochemical and Engineering Aspects ◽

10.1016/j.colsurfa.2014.03.046 ◽

2014 ◽

Vol 451 ◽

pp. 85-89 ◽

Cited By ~ 4

Author(s):

Xiangming Liu ◽

Jintao Tian ◽

Jinqian Jia

Keyword(s):

Fluorescence Emission ◽

Enhanced Fluorescence ◽

Cdte Nanocrystals

Download Full-text

Structural changes in titanium dioxide nanocrystals during plastic deformation

Journal of Applied Crystallography ◽

10.1107/s0021889805020418 ◽

2005 ◽

Vol 38 (5) ◽

pp. 749-756 ◽

Cited By ~ 5

Author(s):

Ulrich Gesenhues

Keyword(s):

Structural Changes ◽

Crystal Size ◽

Lower Layer ◽

High Energy ◽

Primary Crystal ◽

X Ray Diffraction ◽

X Ray ◽

Transmission Electron ◽

Hall Method ◽

Means Of Transmission

The polygonization of 200 nm rutile crystals during dry ball-milling at 10gwas monitored in detail by means of transmission electron microscopy (TEM) and X-ray diffraction (XRD). The TEM results showed how to modify the Williamson–Hall method for a successful evaluation of crystal size and microstrain from XRD profiles. Macrostrain development was determined from the minute shift of the most intense reflection. In addition, changes in pycnometrical density were monitored. Accordingly, the primary crystal is disintegrated during milling into a mosaic of 12–35 nm pieces where the grain boundaries induce up to 1.2% microstrain in a lower layer of 6 nm thickness. Macrostrain in the interior of the crystals rises to 0.03%. The pycnometrical density, reflecting the packing density of atoms in the grain boundary, decreases steadily by 1.1%. The results bear relevance to our understanding of plastic flow and the mechanism of phase transitions of metal oxides during high-energy milling.

Download Full-text