We have performed transport measurements on bridges patterned in misaligned thin films of the superconductor Tl2Ba2CaCu2O8. There is a c-axis component of current flow along the bridge, giving rise to hysteretic Josephson-like current–voltage curves. The temperature dependence of the critical current follows the Ambegaokar–Baratoff theory with IcRN up to 26 mV at 4.2 K. Microwave emission from the Josephson junctions near Tc (≈103 K) has been detected using an X-band detector. We show that 700±15 junctions in the bridge are actively oscillating, confirming that the junctions are “intrinsic” junctions formed by adjacent copper oxide planes in the Tl2Ba2CaCu2O8 crystal structure.

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.

We have measured the transport properties of intrinsic Josephson junction arrays as a function of both temperature and magnetic field, the field being applied perpendicular to the transport current. We show that they depend upon whether the junction width exceeds or is less than the Josephson penetration depth. For widths greater than the Josephson penetration depth, the transport properties are dominated by Josephson vortex flow. For widths less than the Josephson penetration depth, the zero-field dissipation is dominated by Josephson phase diffusion. For non-zero applied fields, there is a good fit to the classical “Fraunhofer” dependence of the critical current upon field in addition to a competition between Josephson phase diffusion and Josephson vortex flow.

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