Zero Bias Conductance in d‐Wave Superconductor/Ferromagnet/d‐Wave Superconductor Trilayers

• Published in: physica status solidi (b) 2018-06, Vol.255 (6), p.n/a
• Main Authors: Popović, Zorica, Miranović, Predrag, Zikic, Radomir
• Format: Article
• Language: English
• Subjects: current transport; d‐wave superconductors; exchange field; superconductor/ferromagnet heterostructures; zero bias conductance
• ISSN: 0370-1972; 1521-3951
• DOI: 10.1002/pssb.201700554

Zero bias conductance (ZBC) in ballistic voltage‐biased d‐wave superconductor/ferromagnet/d‐wave superconductor (DFD) junctions is studied theoretically, for various orientations of superconducting electrodes. We show that ZBC increases with exchange field h in the F barrier, up to some maximum value of h which is of the order of the pair potential in the superconducting electrodes. We find that for a given exchange field, ZBC monotonically decreases with temperature. When the exchange field h is smaller or of the order of the superconducting gap Δ, ZBC has a distinct kink at some characteristic temperature T*. It appears that for this temperature Δ(T*) = h. Thus, observing T* where the kink in the ZBC temperature dependence occurs provides a reliable measurement method to determine exchange fields of the order of the superconducting gap. The influence of exchange field h in the barrier, temperature T, and misorientation of d‐wave superconducting electrodes on zero bias conductance (ZBC) in d‐wave superconductor/ferromagnet/d‐wave superconductor (DFD) junctions is presented. In the small fields domain, the ZBC could be enhanced by increasing the exchange field (up to h ≈ Δ), while the temperature dependence of ZBC may show a kink at T = T* from which it is possible to determine the value of h, since h = Δ(T*).