ISSN:
1573-4803
Source:
Springer Online Journal Archives 1860-2000
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
Abstract Copper-based superconducting alloys including finely dispersed f c c lead or h c p ɛ (Pb- Bi) particles in f c c copper matrix have been obtained by rapid quenching (Cu-M)100-x Pbx and (Cu-M)100-x (Pb0.6Bi0.4 x (M = aluminium, silicon or tin;x 〈 10 at%) alloys containing immiscible elements such as lead and bismuth. The particle size and interparticle distance were about 30 to 130 nm and 20 to 200 nm for had particles and about 30 to 60 nm and 30 to 150 nm for ɛ(Pb- Bi) particles. The transition temperature,T c, was in the range of 3.2 to 5.5 K for the Cu-M-Pb alloys and 6.2 to 6.3 K for the Cu-M-Pb-Bi alloys. Critical magnetic field,H c2, and critical current density,J c, for the later alloys were 0.47 to 0.93T at 4.2 K and 1.1 × 105 to 2.7 × 105 Am−2 at zero applied field and 4.21 K. The mechanism of the appearance of such a soft-type superconductivity for the rapidly quenched copper-based alloys was discussed, and inferred to be due to the formation of a percolation path of a superconducting lead or Pb-Bi phase along the grain boundaries, sub-boundaries and/or tangled dislocations where the lead or Pb-Bi phase precipitated preferentially, rather than the proximity effect based on lead or Pb-Bi particles.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01132412
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