ISSN:
1077-3118
Source:
AIP Digital Archive
Topics:
Physics
Notes:
Compacted (SiO2)100−x(Pb0.6Bi0.4)x (x=20–80 at. %) materials, prepared by mechanical alloying (MA) of amorphous SiO2, fcc Pb, and rhombohedral hexagonal Bi followed by hot pressing of the MA powder at 473 K for 1.8 ks under an applied stress of 250 MPa, were found to have a unique layered structure consisting of amorphous SiO2 and hexagonal close-packed (hcp) ε(Pb-Bi) phases which developed along the direction perpendicular to the uniaxial applied load. The thickness and interlayer distance of the layered ε (Pb-Bi) phase are about 1.5 and 7 μm, respectively, for (SiO2)50Pb30Bi20. Furthermore, the multilayered compacts exhibited a strong anisotropy of electrical resistivity and superconducting properties when their properties are measured along the directions parallel or perpendicular to the layer. Electrical resistivity at 300 K, superconducting critical temperature (Tc), and upper critical magnetic field (Hc2) at 4.2 K are 10.5 μΩ m, 8.5 K, and 2.29 T, respectively, for the parallel direction and 950 μΩ m, 6.9 K, and 0.24 T, respectively, for the perpendicular direction. The strong anisotropy of electrical resistivity and superconducting properties is presumably due to a significant difference in the linkage of electrical path between the parallel and perpendicular directions.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.104279
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