Magnesium diboride, recently discovered as superconductor, is extremely interesting in respect to pairing mechanisms and phonon-mediated superconductivity, but its transition temperature (39K) is decidedly too low for practical applications. A rush for substitutions started, intended to raise Tc and possibly maintain acceptable critical current density. The difficult introduction of Cu was attempted, through a complex procedure employing CuB24 instead of metallic Cu: owing to the tendency of Cu to form inter-metallic compounds with Mg, only a maximum of 3mol% of Cu was safely substituted to Mg in MgB2 lattice and a small parameters contraction proportional to Cu content was recorded. The results are a decrease in Tc of about 0.5 K, not far from that found with Al addition, whose reasons are discussed and interpreted in terms of holes doping.
Effects of copper doping in MgB2 superconductor
RINALDI, DANIELE;BARUCCA, Gianni;CACIUFFO, ROBERTO GIOVANNI MARIA
2002-01-01
Abstract
Magnesium diboride, recently discovered as superconductor, is extremely interesting in respect to pairing mechanisms and phonon-mediated superconductivity, but its transition temperature (39K) is decidedly too low for practical applications. A rush for substitutions started, intended to raise Tc and possibly maintain acceptable critical current density. The difficult introduction of Cu was attempted, through a complex procedure employing CuB24 instead of metallic Cu: owing to the tendency of Cu to form inter-metallic compounds with Mg, only a maximum of 3mol% of Cu was safely substituted to Mg in MgB2 lattice and a small parameters contraction proportional to Cu content was recorded. The results are a decrease in Tc of about 0.5 K, not far from that found with Al addition, whose reasons are discussed and interpreted in terms of holes doping.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
