Correlation between the residual resistance ratio and magnetoresistance in MgB2

Abstract

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, rho vs. T^c, 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) proportional to (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.

10 pages, 3 figures, submitted to Phys. Rev. B (July 6, 2001; revised September 27, 2001); discussion of the need for excess Mg in processing and of the power law dependence of the low temperature resistivity added in response to referee's comments

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• Crystal growth and characterization of MgB2: Relation between structure and superconducting properties
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• Physical property characterization of single step synthesized NdFeAsO0.80F0.20 bulk 50K superconductor
• Topologically-Driven Linear Magnetoresistance in Helimagnetic FeP
• Effects of unreacted Mg impurities on the transport properties of MgB2
• Nonstoichiometry, Defects and Transport Properties in MgB2
• Microstructure and pinning properties of hexagonal-disc shaped single crystalline MgB2
• Synthesis of Mg(B${}_{1-x}$C${}_x$)${}_2$ Powders
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