Title :
HTSC Josephson junctions and dc SQUIDs on SrTiO/sub 3/ bicrystal substrates grown by floating zone method
Author :
Balbashov, A.M. ; Parsegov, I.Yu. ; Kovev, E.K. ; Vengrus, I.I. ; Kupriyanov, M.Yu. ; Polyakov, S.N. ; Snigirev, O.V.
Author_Institution :
Moscow Power Eng. Inst., Russia
fDate :
6/1/1997 12:00:00 AM
Abstract :
A new approach to the fabrication of a SrTiO/sub 3/ bicrystal substrates, based on floating zone growth of natural SrTiO/sub 3/ bicrystals with misorientation angles 24/spl deg/ and 37/spl deg/, has been developed. Thin film YBCO Josephson junctions and dc SQUIDs on SrTiO/sub 3/ bicrystal substrates were fabricated and studied at T=77 K. The critical current density j/sub c/ and I/sub c/R/sub n/ product for the junctions with misorientation angle /spl alpha/=24/spl deg/ were close to 2/spl times/10/sup 4/ A/cm/sup 2/ and 190-260 /spl mu/V, respectively, while for /spl alpha/=37/spl deg/ it was found that j/sub c//spl ap/2/spl times/10/sup 3/ A/cm/sup 2/ and I/sub c/R/sub n//spl ap/90-120 /spl mu/V. The dc SQUIDs were made with typical inductances 20-80 pH, critical currents of 20-150 /spl mu/A and resulting voltage modulation 10-40 /spl mu/V. Noise measurements performed at 77 K revealed low 1/f noise with cut-off frequency about 10 Hz.
Keywords :
1/f noise; Josephson effect; SQUIDs; barium compounds; bicrystals; critical current density (superconductivity); high-temperature superconductors; inductance; strontium compounds; substrates; superconducting device noise; superconducting device testing; yttrium compounds; zone melting; 10 Hz; 20 to 150 muA; 77 K; HTSC Josephson junctions; I/sub c/R/sub n/ product; SrTiO/sub 3/; SrTiO/sub 3/ bicrystal substrates; YBa/sub 2/Cu/sub 3/O/sub 7/; critical current density; critical currents; cut-off frequency; dc SQUIDs; floating zone method; inductances; low 1/f noise; misorientation angles; noise measurements; thin film YBCO Josephson junctions; voltage modulation; Critical current; Critical current density; Fabrication; Josephson junctions; Noise measurement; SQUIDs; Substrates; Transistors; Voltage; Yttrium barium copper oxide;
Journal_Title :
Applied Superconductivity, IEEE Transactions on
