Planar-type tunnel junctions with Bi2Sr2CaCu2O8+δ high-temperature superconducting electrodes and Bi2Sr2YCu2O8+δ artificial barriers

Abstract

We performed a detailed study of the structure and transport properties of Bi2212/22Y2/2212 planar-type tunnel junctions. Both high-temperature superconducting electrodes and semiconducting barriers are highly epitaxial thin films deposited onto SrTiO3 single-crystal (001) substrates. Deposition of the films was carried out by a high oxygen pressure dc-sputtering technique, which produces high-quality epitaxial thin films, as determined by x-ray diffraction, lattice resolution transmission electron microscopy, and Rutherford backscattering. Critical temperatures for the superconducting electrodes of 85 K were determined by transport measurements (ρ and χ versus T). A study of resistivity as a function of temperature of the semiconducting barriers was performed. Clear quasiparticle tunneling indicating a gap structure at about 30–35 mV, a zero-bias peak, as well as linear and flat background at high voltages have been observed. For junctions with very thin barriers weak-link-type behavior was observed. An analysis of the I–V curves for these junctions has been made based on the resistively shunted junction model.

Electric transport in YBa 2 Cu 3 O 7–δ /La 1/3 Ca 2/3 MnO 3 /La 2/3 Ca 1/3 MnO 3 planar‐type

“…The nearly metallic behaviour of the barrier is evidenced on this plot. In many reports on tunnelling experiments, high quality tunnelling barriers displayed resistances of the order of 10 kΩ [8]. Several criteria have been formulated to determine whether tunneling dominates the conduction in superconducting tunneling devices [6].…”

Zero-magnetic-field dynamic scaling inBi2Sr2CaCu2O8Sefrioui1, Arias2, León3 et al. 2004Phys. Rev. BSelf Cite10020View full textAdd to dashboardCite

“…Further details about sample preparation and epitaxial properties can be found elsewhere. [21][22][23] Underdoped samples ͑T c =78 K͒ with a disordered oxygen structure were obtained by vacuum annealing the samples at 500°C as proposed in Ref. 24.…”