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Mg as a main source for the diverse magnetotransport properties of MgB 2

2002; American Physical Society; Volume: 66; Issue: 2 Linguagem: Inglês

10.1103/physrevb.66.020506

1095-3795

Kee Hoon Kim, Jonathan Betts, M. Jaime, A. H. Lacerda, G. S. Boebinger, C. U. Jung, Heon‐Jung Kim, Min‐Seok Park, Sung‐Ik Lee,

Magnetic Properties of Alloys

Magnetotransport properties of pure Mg metal and ${\mathrm{MgB}}_{2}$ samples with varying amounts of unreacted Mg are systematically studied in magnetic fields up to 18 T. With an increasing quantity of Mg, the inhomogeneous ${\mathrm{MgB}}_{2}$ samples show a greatly decreased residual resistivity, an enhanced residual resistance ratio (RRR), and enhanced magnetoresistance (MR), gradually approaching the transport behaviors of pure Mg metal. We use the generalized effective medium theory to show that the large RRR and MR of the inhomogeneous ${\mathrm{MgB}}_{2}$ samples can be quantitatively explained by a two-phase model in which the two phases are ${\mathrm{MgB}}_{2}$ and pure Mg.