We report achievement of a depairing current limit along the c axis in Fe1+yTe1-xSex single crystals. A series of crystals with Tc ranging from 8.6 K to 13.7 K (different amounts of excess Fe, y) were fabricated into c-axis bridges with a square-micrometer cross-section. The critical current density, Jc, was directly estimated from the transport current-voltage measurements. The transport Jc reaches a very large value, which is about one order of magnitude larger than the depinning Jc, but comparable to the calculated depairing Jc∼2×106 A/cm2 at 0 K, based on the Ginzburg-Landau (GL) theory. The temperature dependence of the depairing Jc follows the GL theory [(1-T/Tc)3/2] down to ∼0.83Tc, then increases with a reduced slope at low temperatures, which can be qualitatively described by the Kupriyanov-Lukichev theory. Our study provides a route to understand the behavior of depairing Jc in iron-based superconductors in a wide temperature range.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics