Title :
High T/sub c/ bi-epitaxial junctions and dc SQUIDs structured by focused ion beam etching
Author :
IJsselsteijn, R.P.J. ; Hilgenkamp, J.W.M. ; Velhhuis, D. ; Flokstra, J. ; Rogalla, H. ; Traeholt, C. ; Zandbergen, H.W.
Author_Institution :
Dept. of Appl. Phys., Twente Univ., Enschede, Netherlands
fDate :
6/1/1995 12:00:00 AM
Abstract :
Focused ion beam etching has been used to pattern dc SQUIDs into previously characterised template bi-epitaxial grain boundary junctions. Using this technique the screening parameter /spl beta//sub L/ can be optimised for a chosen temperature (in our case 30 K). Electrical characteristics, including noise measurements, are presented. A minimal white noise level of 22 /spl mu//spl phi//sub 0//spl middot/Hz/sup -1/2/ (1.8/spl middot/10/sup -29/ J/spl middot/Hz/sup -1/) has been obtained at 20 K. Using bias current modulation the 1/f noise could almost completely be suppressed down to 1 Hz in the entire temperature range (10-65 K).<>
Keywords :
1/f noise; Josephson effect; SQUIDs; barium compounds; critical current density (superconductivity); focused ion beam technology; grain boundaries; high-temperature superconductors; sputter etching; superconducting device noise; superconducting device testing; superconducting epitaxial layers; white noise; yttrium compounds; 1 Hz to 1 kHz; 1/f noise suppression; 10 to 65 K; CeO/sub 2/; CeO/sub 2/ template layer; DC SQUIDs; HREM; MgO; MgO substrate; YBa/sub 2/Cu/sub 3/O/sub 7/; bias current modulation; critical current density; electrical characteristics; flux noise; focused ion beam etching; high T/sub c/ biepitaxial junctions; patterning; screening parameter; temperature range; template biepitaxial grain boundary junctions; white noise level; Argon; Bars; Critical current; Etching; Fabrication; Grain boundaries; Inductance; Ion beams; Ion sources; SQUIDs;
Journal_Title :
Applied Superconductivity, IEEE Transactions on
