Transactions of Nonferrous Metals Society of China
JOURNAL OF RAILWAY SCIENCE AND ENGINEERING
|Vol. 13 No. 4 August 2003|
（1. Department of Mechanical Engineering,
Tsinghua University, Beijing 100084, China
2. Department of Physics, Tsinghua University, Beijing 100084, China）
Abstract:Mg1-xMxB2(M=Li or deficiency) compounds were prepared and their structure and superconducting properties were studied. The results show that nearly single-phased Mg1-xLixB2 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 Tc of Mg1-xLixB2 decreases. Moreover, loss of superconductivity occurs for sample with x=0.5. For Mg1-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 Tc decreases. The obvious difference in the superconductivity of Mg1-xLixB2 and Mg1-xB2 suggests that Li indeed dopes into the structure of MgB2.
Key words: Mg1-xLixB2; Mg1-xB2; lattice parameter; superconducting transition temperature