Study of high temperature resistivity and thermal stability of superconductor MgB2

摘要

The single phase and polycrystalline MgB2 superconductor was synthesized by the Mg diffusion method and its temperature dependence of resistivity was studied from T, up to 460 K. The normal state temperature dependence of electrical resistivity is linear above 270 K and can be fitted well by the Bloch-Gruneisen expression with the Debye temperature theta(D) = 1200 K for the temperature range from 40 to 450 K. There is an unexpected abrupt jump in rho(T) curve near 450 K. Thermal-gravity and differential thermal-analysis (TG-DTA) indicated this jump of rho(T) could be caused by the oxidation of few Mg impurities in air atmosphere. (C) 2002 Elsevier Science B.V. All rights reserved. [References: 21]