High current superconductivity in FeSe0.5Te0.5-coated conductors at 30 tesla

Abstract

Although high-temperature superconductor cuprates have been discovered for more than 25 years, superconductors for high-field application are still based on low-temperature superconductors, such as Nb(3)Sn. The high anisotropies, brittle textures and high manufacturing costs limit the applicability of the cuprates. Here we demonstrate that the iron superconductors, without most of the drawbacks of the cuprates, have a superior high-field performance over low-temperature superconductors at 4.2 K. With a CeO(2) buffer, critical current densities >10(6) A cm(-2) were observed in iron-chalcogenide FeSe(0.5)Te(0.5) films grown on single-crystalline and coated conductor substrates. These films are capable of carrying critical current densities exceeding 10(5) A cm(-2) under 30 tesla magnetic fields, which are much higher than those of low-temperature superconductors. High critical current densities, low magnetic field anisotropies and relatively strong grain coupling make iron-chalcogenide-coated conductors particularly attractive for high-field applications at liquid helium temperatures.

Magneto-optical characterizations of FeTe0.5Se0.5thin films with critical current density over 1 MA cm−2

“…On the other hand, its simple structure and less toxic nature are also preferable for fabricating wires and thin films, although the critical current density, J c , in FeTe 0.5 Se 0.5 bulks and wires [6,7] is still much lower than that of the Ba 0.6 K 0.4 Fe 2 As 2 wires [8]. Our previous reports have demonstrated that high-quality FeTe 0.5 Se 0.5 thin films can maintain a large J c over 10 6 A/cm 2 at 4.2 K. Even under the field of 30 T, J c 's are still exceeding 10 5 A/cm 2 [9,10]. For the practical application of superconducting wires and tapes, local characterizations of J c distribution are very important.…”

Critical current density, vortex dynamics, and phase diagram of single-crystal FeSe

“…21 On the other hand, its relatively low T c is also meaningful to understand the crossover between HTS and low temperature superconductors, and to examine the validity of vortex-related theory in a much broader temperature range.…”

Huge critical current density and tailored superconducting anisotropy in SmFeAsO0.8F0.15 by low-density columnar-defect incorporation

“…However, the overriding application metric, the maximum loss-less electrical current density, is ultimately determined by the vortex pinning that can be engineered into the material. Significant advances towards highperforming superconducting materials based on the so-called 122-compounds, most notably Ba(Fe 1 À x Co x ) 2 As 2 and Ba 1 À x K x Fe 2 As 2 (refs 6-8), and 11-compounds 9 have been made. For instance, Ba 0.6 K 0.…”