Raman study of element doping effects on the superconductivity of MgB2

Authors

Wenxian Li, University of WollongongFollow
Yongqing Li, Shanghai University
R H. Chen, University of Wollongong
Rong Zeng, University of WollongongFollow
S. X. Dou, University of WollongongFollow
M Y. Zhu, Shanghai University
H M. Jin, Shanghai University

RIS ID

23556

Publication Details

Li, W., Li, Y., Chen, R., Zeng, R., Dou, S. X., Zhu, M. & Jin, H. (2008). Raman study of element doping effects on the superconductivity of MgB2. Physical Review B (Condensed Matter and Materials Physics), 77 (9), 094517-1-094517-7.

Abstract

The influences of phonon frequency and unit cell volume on the superconductivity of element-doped MgB₂ are discussed with reference to a Raman study on SiC, C, Mn, and Al-Ag-doped Mg-B materials. A phenomenon has been found in the doped samples, in that the phonon frequency changes to counteract the crystal lattice variation to keep the system stable within a Grüneisen parameter of 2.0–4.0. The chemical doping effects on phonon frequency and unit cell volume can be explained by the harmonicity-anharmonicity competition in the compounds. A decreased electronic density of states is responsible for the depression of superconductivity that is seen in doped MgB₂. The possibility of a high critical temperature, T_c, in the Mg-B system exists if the material can possess both a high phonon frequency and a big unit cell volume at the same time, as indicated by the isotope effect and hydrogenation experiments.

Grant Number

ARC/DP0770205

Additional Grant Number

http://purl.org/au-research/grants/ARC/DP0770205