Fabrication and measurement of intrinsic Josephson junctions in misaligned films of Tl/sub 2/Ba/sub 2/CaCu/sub 2/O/sub 8/

Abstract

Abstruct-Instrinsic Josephson bridges have been patterned in films of T12Ba2CaCu208. Due to our device geometry we have used films that are misaligned at 20" to the substrate surface. This misalignment has been confirmed using four-circle x-ray diffraction and cross-sectional transmission electron microscopy. Our films still retain a high critical temperature (108K) despite their misalignment. The resistive anisotropy of the film is comparable to single crystal data. The product of the critical current and normal state resistance is equal to 14mV at 4.2K and is independent of the critical current density. These two achievements are attributed to the lack of engineered interfaces in our intrinsic junctions. A run-to-run variation in the critical current is explained by the presence of nonJosephson shunts in the junction. Junctions with fewer nonJosephson shunts show greater hysteresis.

Sub-micron thin film intrinsic Josephson junctions

“…During the annealing process the TBCCO film recrystallises epitaxially on the vicinal substrate with the result that the copper-oxide double planes are mis-aligned by 20 with respect to the substrate surface. This epitaxy is confirmed both by four-circle x-ray diffraction and cross-sectional transmission electron micrography [9].…”

Decoupling of a current-biased intrinsic Josephson junction from its environment

“…The bridge reported here therefore contains 460±50 IJJ's, the uncertainty arising due to the fact that the ends of the bridge are not well defined with respect to the sloping copper-oxide double planes. The TBCCO epitaxy is confirmed both by x-ray diffraction and transmission electron micrography 12 . Four terminal contacts are made to the bridges along TBCCO lines patterned in the same film.…”

THz radiation sensing and emission: The phase-locking properties of Josphson junction arrays coupled with THz frequency Fabry-Perot resonators

“…However, the equivalent circuit model of Josephson junction shunted by LC series circuit cannot reflect the practical situations. For example, the anti-phase-locking state of the junctions is obtained in the reference [7], but this is not correct and there is no experiment result to support it. When an LC series circuit is under resonance condition, which is just a short circuit, no detectable alternating signal can be measured, so that the anti-phase locking state is get.…”

“…*Contacting Author: Yating Hu is with the Superconducting Laboratory, Nankai University; 300071, Tianjin, China. Email: huytnankai@yahoo.com.cn intrinsic Josephson junctions; one is using Bi-2212 single crystals or whiskers [5] [6] and the other is using misaligned Tl-2212 films [7] . The advantage of fabrication with Tl-2212 films is that it can produce a large number of Josephson junctions in one array with nearly identical properties.…”