Title :
Fabrication of high quality YBa/sub 2/Cu/sub 3/O/sub y/ thin films using pulsed laser deposition
Author :
Eun-Hong Lee ; Sang-Jin Park ; I-Hun Song ; Insang Song ; Junho Gohng ; Junghyun Sok ; Jo-Won Lee ; Duk Young Jeon ; Dosquet, C.Y.
Author_Institution :
Samsung Adv. Inst. of Technol., Suwon, South Korea
fDate :
6/1/1997 12:00:00 AM
Abstract :
High quality YBa/sub 2/Cu/sub 3/O/sub y/ (YBCO) thin films for directly coupled DC-SQUIDs were fabricated by pulsed laser deposition. Several critical parameters have been optimized through systematic studies. The best quality YBCO thin films on MgO and on LaAlO/sub 3/ substrates were made under the O/sub 2/ pressure of 400/spl sim/500 mTorr at the substrate temperature of 780/spl sim/800/spl deg/C and target to substrate distance of 50/spl sim/60 mm. Films showing a T/sub c/ above 91 K and J/sub c/ above 2/spl times/10/sup 6/ A/cm/sup 2/ at 77 K were routinely obtained. Extensive AFM and x-ray diffraction studies have been conducted for morphological and structural analyses. The directly coupled DC-SQUIDs were fabricated from the YBCO thin films deposited on SrTiO/sup 3/ bicrystals under the optimized conditions. Measurement of 2I/sub c/ and swing voltage gives values of 420 /spl mu/A and 30 /spl mu/V at 77 K, respectively.
Keywords :
atomic force microscopy; barium compounds; critical current density (superconductivity); high-temperature superconductors; pulsed laser deposition; superconducting thin films; superconducting transition temperature; surface topography; yttrium compounds; 400 to 500 mtorr; 50 to 60 mm; 77 K; 780 to 800 C; 91 K; LaAlO/sub 3/; MgO; X-ray diffraction; YBa/sub 2/Cu/sub 3/O/sub 7/; atomic force microscopy; critical parameters; high quality YBa/sub 2/Cu/sub 3/O/sub y/ thin films; high temperature superconductor; pulsed laser deposition; substrate temperature; target to substrate distance; Optical coupling; Optical device fabrication; Optical pulses; Pulsed laser deposition; Sputtering; Temperature; Transistors; Voltage; X-ray diffraction; Yttrium barium copper oxide;
Journal_Title :
Applied Superconductivity, IEEE Transactions on
