The resistivity and magnetoresistance in the normal state for bulk and thin-film MgB2 with different nominal compositions have been studied systematically. These samples show different temperature dependences of normal-state resistivity and residual resistance ratios although their superconducting transition temperatures are nearly the same, except for the thin-film sample. The correlation between the residual resistance ratio (RRR) and the power-law dependence of the low-temperature resistivity, p vs Tc, indicates that the electron-phonon interaction is important. It is found that the magnetoresistance (MR) in the normal state scales well with the RRR, a0(MR)∝(RRR)2.2±0.1 at 50 K. This accounts for the large difference in magnetoresistance reported by various groups, due to different defect scatterings in the samples.
|Number of pages||5|
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|Publication status||Published - 2002 Jan 1|
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics