Intrinsic Josephson Junctions in Bi-2212 Thin Films Fabricated by Metal-Organic Decomposition

摘要

We fabricated a mesa $10 mu{rm m}times 10 mu{rm m}$ in area and $sim$150 nm in height on a single grain in a 240-nm ${rm Bi}_{2}{rm Sr}_{2}{rm CaCu}_{2}{rm O}_{8+delta}/{rm MgO}$ thin-film grown by metal-organic decomposition (MOD) with face-to-face annealing. A multi-branch structure peculiar to intrinsic Josephson junctions (IJJs) was observed in the $I-V$ characteristics of the fabricated mesa, and this structure was characterized by approximately 100 quasiparticle branches with critical current densities of 1 ${rm kA/cm}^{2}$ and voltage-jump intervals of 20 mV. Moreover, the temperature dependence of the critical current was in good agreement with a theoretical result based on $c$ -axis Josephson tunneling in $d$-wave superconductors. These results imply that the thin films grown by MOD have sufficient quality to fabricate IJJs for practical terahertz applications.