Study of In‐Situ Laser‐Deposition of Superconducting Thin Films by In‐Situ Resistance Measurement

1989 ◽  
Vol 169 ◽  
Author(s):  
Q.Y. Ying ◽  
H.S. Kim ◽  
D.T. Shaw ◽  
H.S. Kwok
Keyword(s):  
Thin Films ◽  
Real Time ◽  
Final Stage ◽  
Temporal Change ◽  
Interface Reaction ◽  
Laser Deposition ◽  
Laser Evaporation ◽  
Superconducting Thin Films ◽  
Electric Resistance

AbstractThe electric resistance was measured in real time during laser evaporation deposition of superconducting thin films. It was found that different substrates led to different behaviors in the temporal change of the resistance. The results are consistent with the processes of nucleation, interface reaction and bulk‐like growth. Structural transformation was also observed due to oxygen backfilling at the final stage of the deposition.

In‐Situ Fabrication of YBa2Cu3O7‐x Superconducting Thin Films Directly on Silicon Substrates with Tc0 > 77K

1989 ◽  
Vol 169 ◽  
Author(s):  
C. B. Lee ◽  
R. K. Singh ◽  
S. Sharan ◽  
A. K. Singh ◽  
P. Tiwari ◽  
...  
Keyword(s):  
Thin Films ◽  
Laser Pulses ◽  
Superconducting Film ◽  
Laser Evaporation ◽  
Silicon Substrates ◽  
Superconducting Thin Films ◽  
Si Substrates ◽  
In Situ Fabrication ◽  
Substrate Temperatures

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.

Effects of Processing Parameters on the Excimer Laser Deposition of Yba2Cu3O7-δ Thin Films

1989 ◽  
Vol 169 ◽  
Author(s):  
R. E. Muenchausen ◽  
X. D. Wu ◽  
R. C. Dye ◽  
K. M. Hubbard ◽  
R. C. Estler ◽  
...  
Keyword(s):  
Thin Films ◽  
Laser Energy ◽  
Processing Parameters ◽  
Spot Size ◽  
Laser Deposition ◽  
Angular Distributions ◽  
Superconducting Thin Films ◽  
Film Properties ◽  
Optimized Conditions

AbstractSystematic studies of the effects of pulsed laser deposition processing parameters on plume dynamics and resultant film properties have been performed. Plume angular distributions, cosm(θ), were observed to be variable between 1 > m > 15 depending on laser energy density and spot size. Under optimized conditions, epitaxial, superconducting thin films could be grown in‐situ on a variety of single‐crystal substrates. High quality, 2000 Å  ss thick films were obtained at deposition rates approaching 150 Å/sec.

Physics Of In-Situ Laser Deposition Of Superconducting Thin Films

1990 ◽  
Author(s):  
H. S. Kwok ◽  
D. T. Shaw ◽  
Q. Y. Ying ◽  
J. P. Zheng ◽  
S. Witanachchi ◽  
...  
Keyword(s):  
Thin Films ◽  
Laser Deposition ◽  
Superconducting Thin Films

Laser Deposition of CdS Thin films on Various Substrates

1990 ◽  
Vol 201 ◽  
Author(s):  
L. Shi ◽  
Y. Hashishin ◽  
S. Y. Dong ◽  
H. S. Kwok
Keyword(s):  
Thin Films ◽  
Film Formation ◽  
Laser Deposition ◽  
Laser Evaporation ◽  
Superconducting Transition ◽  
X Ray Diffraction ◽  
Electrical Measurements ◽  
Cds Thin Films ◽  
Cds Films

AbstractWe have deposited CdS thin films onto substrates such as glass, sapphire and high Tc YBCO superconducting films by Nd:YAG laser evaporation in a vacuum environment. X-ray diffraction, optical and electrical measurements were used to study the deposited CdS films. The films are highly oriented with c-axis perpendicular to the surface and are optically smooth. The effects of laser fluence, substrate temperature on the film quality will be discussed. Additionally, Indium doped CdS films were also grown on sapphire substrates by laser deposition. In-situ resistivity measurements were employed to study the film formation process during laser deposition. A simple model was given to explain the in-situ resistivity data. Finally, a deposition temperature window was found to produce good quality CdS/YBCO heterostructures. The superconducting transition temperature of the YBCO films was degraded to 68K from an original Tc of 85 K after CdS deposition. The degradation of the superconducting properties was found mainly due to the interactions in the interface region.

In‐Situ Patterning and Critical Current Density Measurements in Laser Deposited High‐Tc Superconducting Thin Films

1989 ◽  
Vol 169 ◽  
Author(s):  
R. K. Singh ◽  
C. B. Lee ◽  
P. Tiwari ◽  
J. Narayan
Keyword(s):  
Thin Films ◽  
Critical Current Density ◽  
Critical Current ◽  
Current Density ◽  
Deposition Process ◽  
Laser Deposition ◽  
Zero Magnetic Field ◽  
Transport Critical Current Density ◽  
Superconducting Thin Films

AbstractWe have performed transport critical current density, Jc, measurements on epitaxial superconducting thin films which were in‐situ patterned during the laser deposition process. Shadow masks of various dimensions were placed close to the substrate to generate different patterns. Epitaxial films of YBa2Cu3O7 on (100) SrTiO3, (100) YSZ, and (100) LaA1O3 substrates were fabricated at low processing temperatures (500‐650°Q by the biased laser deposition technique in an oxygen ambient of 200 mtorr. Excellent quality superconducting thin films were formed on patterned areas. The critical temperature of the films was found to be in the range of 88 to 90 K, and the best critical current density values (at 77K, and zero magnetic field) greater than 6.5 x106 Amps/cm2 were obtained for silver doped YBa2Cu3O7 films on (100)LaAlO3 substrates.

Pulsed Laser Deposition of High Tc Superconducting Thin Films: Deposition Physics and in-Situ Processing

1989 ◽  
Vol 169 ◽  
Author(s):  
Rajiv K. Singh ◽  
J. Narayan
Keyword(s):  
Thin Films ◽  
Three Dimensional ◽  
Pulsed Laser ◽  
Laser Evaporation ◽  
Superconducting Thin Films ◽  
High Tc ◽  
Ion Channeling ◽  
In Situ Fabrication ◽  
Current Densities

AbstractThe pulsed laser evaporation (PLE) technique for deposition of thin films is characterized by a number of unique properties. Based on the experimental characteristics, a theoretical model is developed which considers the formation and anisotropic three dimensional expansion of the laser generated plasma. This model explains most of the experimental features observed in PLE. We have also employed the PLE technique for in-situ fabrication of YBa2Cu3O7 superconducting thin films on different substrates in the temperature range of 500–650°C. At temperatures below 600–C, a biased interposing ring between the substrate and the target was found to significantly improve the superconducting properties. The minimum ion channeling yields were between 3-3.5 % for films deposited on (100) SrTiO3 and (100) LaA1O3 substrates. The films exhibit very high critical current densities (Jc) with maximum values exceeding 6.5 x 106 amps/cm2 for silver doped YBa2Cu3O7 films on (100) LaA1O3 substrates, and the Jc also varies anisotropically with the magnetic field.

Preparation of BaTiO3 thin films using pulsed KrF laser deposition and IN SITU laser annealing

1998 ◽  
Vol 20 (1-4) ◽  
pp. 87-94
Author(s):  
Atsushi Ito ◽  
Akihiko Machida ◽  
Minoru Obara
Keyword(s):  
Thin Films ◽  
Laser Annealing ◽  
Laser Deposition ◽  
Krf Laser
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