Transport properties in FeSe_(0.5)Te_(0.5) nanobridges

摘要

FeSeTe nanobridges of different widths have been fabricated on MgO substrates using focused ion beams. These nanobridges exhibit the Josephson effects. The current-voltage curves of junctions with 248-564 nm wide follow the resistively and capacitatively shunted junction model. Shapiro steps under microwave radiation were clearly observed in these nanobridges. The products of the critical current and normal state resistance (I_cR_n) are remarkably high. The temperature dependence of I_cR_n product followed the Ambegaokar-Baratoff (A-B) relation. The value of energy gap of FeSeTe calculated from the A-B relation is 3.5k_BT_c. The nanobridge junctions have a strong potential for high frequency applications.