Back to Search
Start Over
Phase formation of polycrystalline MgB2 at low temperature using nanometer Mg powder
- Source :
-
Solid State Communications . Jul2004, Vol. 131 Issue 3/4, p275. 4p. - Publication Year :
- 2004
-
Abstract
- The MgB2 superconductor synthesized in a flowing argon atmosphere using nanometer magnesium powder as the raw materials, denoted as Nano-MgB2, has been studied by the technique of in situ high temperature resistance measurement (HT-RT measurement). The MgB2 phase is identified to form within the temperature range of 430–490 °C, which is much lower than that with the MgB2 sample fabricated in the same gas environment using the micron size magnesium powder, denoted as Micro-MgB2 and reported previously. The sample density of the Nano-MgB2 reaches 1.7 g/cm3 with a crystal porosity structure less than a μm, as determined by the scanning electron microscope (SEM) images, while the Micro-MgB2 has a much more porous structure with corresponding density of 1.0 g/cm3. This indicates that the Mg raw particle size, beside the sintering temperature, is a crucial factor for the formation of high density MgB2 sample, even at the temperature much lower than that of the Mg melting, ∼650 °C. The X-ray diffraction (XRD) pattern shows a good MgB2 phase with small amount of MgO and Mg and the transition temperature, <f>TC,</f> of the Nano-MgB2 was determined to be 39 K by temperature dependent magnetization measurements <f>(M–T),</f> indicating good superconducting properties. [Copyright &y& Elsevier]
- Subjects :
- *ELECTRON microscopes
*SCANNING electron microscopes
*MAGNESIUM
*HIGH temperatures
Subjects
Details
- Language :
- English
- ISSN :
- 00381098
- Volume :
- 131
- Issue :
- 3/4
- Database :
- Academic Search Index
- Journal :
- Solid State Communications
- Publication Type :
- Academic Journal
- Accession number :
- 13590185
- Full Text :
- https://doi.org/10.1016/j.ssc.2004.03.058