(Color online) (a) Schematic cross-sectional view of the ramp with both PCCO x = 0.15 superconducting electrodes (gray) separated by a PCCO x = 0.05 barrier (black). The figure shows also the top amorphous (green) and the bottom substrate (striped brown). (b) AFM data of the ramp profile over a width of about 5.6 m. The dotted line shows the position of the interface between STO-A and the bottom PCCO electrode. From this data, we extract an average ramp angle of with respect to the surface of the substrate. (c) AFM data showing the rough STO-A layer on top of the PCCO bottom electrode prior to the deposition of the nonsuperconducting PCCO barrier and the top PCCO superconducting electrode film. One should note that the Z scale does not match those for X and Y.
IV curves for junctions with superconducting electrodes with in subpanels (a) and (b), in subpanels (c) and in (d).
Critical current as a function of applied magnetic field for PCCO x = 0.15 with a barrier of 22.5 nm of PCCO x = 0.05 at (a) 4.2 K and (b) 9 K. Solid lines are guides for the eye.
(Color online) Shapiro steps observed in the IV curves measured on a 56 m wide PCCO junction at 4.2 K. (a) as a function of frequency (top panel: 10 GHz, middle: 15 GHz, bottom: 20.5 GHz); (b) as a function of RF power at 20.5 GHz: from top to bottom - 2 , 6, and 12 dbm.
(Color online) Temperature dependence of the critical current density for a junction with electrodes at , a barrier thickness of 22 nm and width of 145 m. The solid (red) line is a fit to in the temperature range from 0.4 to .
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