2008/02/14 by Myung-Ho Bae, Myung‐Ho Bae, R. C. Dinsmore III +11
Materials Science · Physics and Astronomy · #Electronic and Structural Properties of Oxides #FOS: Physical sciences #Physics of Superconductivity and Magnetism #Superconductivity (cond-mat.supr-con) #Superconductivity in MgB2 and Alloys #cond-mat.supr-con
paper · pdf · doi:10.48550/arxiv.0802.2091
accepted in Phys. Rev. B
arxiv created 2008/02/14 · openalex publication_date 2008/02/14 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Microwave response of S-shaped Bi2Sr2CaCu2O8+x (Bi-2212) micron-scale samples, in which the supercurrent was forced to flow perpendicular to the crystal layers, was investigated. A treatment with a focused ion beam allowed us to reduce the plasma frequency down to fp∼5 GHz at T=0.3 K in naturally stacked Josephson junctions in a crystal. We observed Shapiro steps at frequencies as low as ∼5 GHz. Well-developed zero-crossing Shapiro steps were observed at frequencies as low as ∼10 GHz. They appeared as constant-voltage plateaus with a non-zero voltage occurring at zero bias current. We confirmed that zero-crossing Shapiro steps in the Bi-2212 stacked junctions can be observed when the irradiated frequency is sufficiently larger than fp. The observed high-order fractional steps in the microwave responses indicate that the interlayer-coupled Bi-2212 Josephson junctions have nonsinusoidal current-phase relation. Based on the temperature dependence of the steps we also showed that the finite slope of the steps is due to the enhancement of the phase diffusion effect.