IN-SITU Diagnostics For Deposition And Processing Of High T c Superconducting Thin Films

1990 ◽  
Author(s):  
T. Venkatesan
1992 ◽  
Vol 06 (08) ◽  
pp. 477-483 ◽  
Author(s):  
QINGXIN SU ◽  
SHIFA XU ◽  
DAFU CUI ◽  
HUIBIN LU ◽  
YONGJUN TIAN ◽  
...  

High-T c superconducting thin films of YBa 2 Cu 3 O 7 were grown in-situ on (100) SrTiO 3 substrates by Nedymium:yttrium aluminum garnet [Nd:YAG] laser ablation. The effects of the substrate temperature on the transition temperature, microcrystalline structure and surface morphology of the films were discussed. Best results were obtained in the 730°–770°C range. X-ray diffraction analysis showed that these films were highly c-oriented with the c-axis perpendicular to the substrate surface. At the optimum substrate temperature, a very smooth morphology with only a few small particles were observed by scanning electron microscopy. The zero resistance temperature of these films were ≥ 90 K with a narrow transition width and the ac susceptibility measurement also gave the same result. The highest critical current density obtained at 77 K and zero magnetic field was 3.8 × 106 A/cm 2.


1989 ◽  
Vol 169 ◽  
Author(s):  
C. B. Lee ◽  
R. K. Singh ◽  
S. Sharan ◽  
A. K. Singh ◽  
P. Tiwari ◽  
...  

AbstractWe report in‐situ fabrication of c‐axis textured YBa2Cu3O7‐x superconducting thin films with Tco > 77K on unbuffered silicon substrates by the biased pulsed laser evaporation (PLE) technique in the temperature range of 550‐650°C. At substrate temperatures below 550°C, no c‐axis texturing of the superconducting film was observed. The YBa2Cu3O7‐x superconducting films were fabricated by ablating a bulk YBa2Cu3O7 target by a XeCl excimer laser (λ = 308 nm, τ = 45 × 10‐9 sec) in a chamber maintained at an oxygen pressure of 0.2 torr . The thickness of the films was varied from 0.3 to 0.5 nm depending on the number of laser pulses. Extensive diffusion was observed in thin films deposited at substrate temperatures above 550°C. However, microstructurally, with increase in the substrate temperature the films exhibited larger grain size and greater degree of c‐axis texturing (measured by the ratio of the (005) and (110) X‐ray diffraction peaks). This was found to give rise to better superconducting properties with Tco exceeding 77 K for YBa2Cu3O7‐x films deposited on Si substrates at 650°C.


Nature ◽  
1992 ◽  
Vol 355 (6358) ◽  
pp. 327-328 ◽  
Author(s):  
K. Endo ◽  
H. Yamasaki ◽  
S. Misawa ◽  
S. Yoshida ◽  
K. Kajimura

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