Influence of doping effect on structure and superconducting properties of MgB₂

来源期刊：中国有色金属学报(英文版)2003年第4期

论文作者：熊玉华 李培杰 张晓平 赵永刚 曹必松 曾大本

文章页码：912 - 916

Key words：Mg_1-xLi_xB₂; Mg_1-xB₂; lattice parameter; superconducting transition temperature

Abstract: Mg_1-xM_xB₂(M=Li or deficiency) compounds were prepared and their structure and superconducting properties were studied. The results show that nearly single-phased Mg_1-xLi_xB₂ samples have been obtained while x≤0.3. With increasingx, lattice parameters a decreases and c shows no obvious change, and the superconducting transition temperature T_c of Mg_1-xLi_xB₂ decreases. Moreover, loss of superconductivity occurs for sample with x=0.5. For Mg_1-xB₂ nearly single-phased samples can be obtained at x=0. MgB₂ coexists with MgB₄ phase and some minor impurity phases while 0＜x＜0.5. With the increase of x, a and c of MgB₂ decreases and increases, respectively, and T_c decreases. The obvious difference in the superconductivity of Mg_1-xLi_xB₂ and Mg_1-xB₂ suggests that Li indeed dopes into the structure of MgB₂.