Superior MgB(2) superconducting wire performance through oxygen-free pyrene additive
"There is great potential to further enhance the critical current density (J(c)) performance of MgB(2) wires. Herein, MgB(2) wires were fabricated by using oxygen-free pyrene as dopant, and field and temperature dependences of J(c) were systematically evaluated. In addition, a strong correlation among sintering temperature, structural parameters, microstructure, and superconducting performance was established. High lattice distortion was obtained by using pyrene as an additive as well as by using a low-temperature sintering process. This arises from vacancy formation, as confirmed by first-principles calculations. The microscopic defects introduce impurity scattering, resulting in the enhancement of the irreversibility field and J(c). (C) 2012 The Japan Society of Applied Physics"