Microstructure and microwave surface resistance of YBaCuO thin films

Kästner, G.; Schäfer, Christian; Senz, Stephan; Hesse, D.; Lorenz, Michael; Hochmuth, H.; Getta, M.; Hein, Matthias; Kaiser, Thomas; Müller, Günter

doi:10.1109/77.784898

Cited by 15 publications

(4 citation statements)

References 8 publications

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“…The mismatch and the difference in thermal expansion coefficients prevents the preparation of thick films. In the case of YBCO the maximum thickness for crack-free films on CeO 2 buffered sapphire is mostly restricted to about 300 nm (see, for example, Kästner et al (1999) who produced YBCO films by pulsed laser deposition). By introducing structural defects into the YBCO films via a modification of the deposition parameters in the sputtering process Wördenweber et al (1999) succeeded in the preparation of YBCO films on CeO 2 buffered sapphire as thick as 700 nm.…”

Section: Tl-2212 On Sapphirementioning

confidence: 99%

TlBaCaCuO-(2212) thin films on lanthanum aluminate and sapphire substrates for microwave filters

Schneidewind¹,

Manzel²,

Bruchlos³

et al. 2001

Supercond. Sci. Technol.

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High-quality Tl 2 Ba 2 CaCu 2 O 8 films for microwave filter application are prepared on both sides of 2 inch lanthanum aluminate substrates as well as on double-sided CeO 2 coated r-cut sapphire substrates. The films have thicknesses as high as 1 µm in the case of lanthanum aluminate substrates. On CeO 2 buffered sapphire substrates it is possible to prepare crack-free superconducting films as thick as 400 nm. For both substrate materials we reach high critical current densities of J c > 2 × 10 6 A cm −2 at 77 K. The microwave surface resistances R s were measured to fall short of 100 µ at 5.6 GHz and 77 K in the low-field case, comparable to the best films made of YBa 2 Cu 3 O 7−x material. The films were able to tolerate high microwave power levels corresponding to magnetic field amplitudes of B RF > 2 mT. The critical temperature exceeds 102 K. This excellent performance is maintained even after several thermal cycles. The films were used to produce four-pole band-pass filters for the C-band which were operated without any detectable loss in their transfer characteristics up to temperatures of about 85 K. This is the first time that large area (2 inch) double-sided Tl 2 Ba 2 CaCu 2 O 8 films have been prepared on sapphire with excellent critical current density in conjunction with low surface resistance.

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Section: Tl-2212 On Sapphirementioning

confidence: 99%

TlBaCaCuO-(2212) thin films on lanthanum aluminate and sapphire substrates for microwave filters

Schneidewind¹,

Manzel²,

Bruchlos³

et al. 2001

Supercond. Sci. Technol.

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“…The former is termed the critical current per unit width, I c /w, which is expressed as the product of the critical current density J c and the film thickness d. In order to derive a high value of I c /w, it is therefore necessary to obtain higher values of J c and/or thicker films. However, further increase of YBCO film thickness has been restricted by microcracking [5,6] which occurs beyond a critical value, a phenomenon that results from the difference in coefficient of thermal expansion between the sapphire substrate and the YBCO film. Hitherto the problem has been limited to improving the value of J c for films with thickness below the critical value, ascertained to be around the range of ∼0.3 µm.…”

Section: Introductionmentioning

confidence: 99%

Thickness dependence ofJ_cfor YBCO thin films prepared by large-area pulsed laser deposition on CeO₂-buffered sapphire substrates

Develos-Bagarinao

Yamasaki

Nie

et al. 2005

Supercond. Sci. Technol.

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We evaluated for the first time the thickness dependence of the critical current density (Jc) of micrometre thick YBCO films on CeO2-buffered sapphire. YBCO films were successfully grown in microcrack-free form up to a thickness of by large-area pulsed laser deposition. Jc was found to decrease exponentially with YBCO thickness. Results suggest that the reduction in Jc with film thickness can be attributed to an evolving film microstructure as a function of thickness, as well as a corresponding change in the defect structures responsible for flux pinning. It was observed that film porosity and roughness increased with film thickness due to the growth and encroachment of the BaY2O4 phase. To clarify the flux pinning mechanism, we measured the angular dependence of Jc for films of different thicknesses and correlated this with the defect structure as revealed from the etch pit method and atomic force microscopy (AFM) observations. An unusually prominent Jc peak was observed when , which is due to correlated extended defects parallel to the c-axis of YBCO. Examination of the film microstructure revealed two defect types that give rise to the Jc peak: linear defects in the form of screw and edge dislocations, and planar defects possibly in the form of stacking faults. The density of linear defects decreased with film thickness whereas that of the planar defects increased considerably. From the behaviour of Jc with film thickness, these results suggest that linear defects may be more effective pinning centres than planar defects, or that an overabundance of planar defects may offset the increase of Jc for thick films.

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“…Electron scattering is influenced by elements like material purity, temperature, and microwave field strength. Researchers and engineers aim for high-purity YBCO materials and precise operating conditions to minimize electron scattering effects [34].…”

Section: Electron Scatteringmentioning

confidence: 99%

Review on Microwave Surface Resistance of High Temperature Superconductor Yttrium Barium Copper Oxide

Dahal,

Wang

2024

Preprint

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The performance of Yttrium-Barium Copper Oxide (YBCO) high-temperature superconductors in high-frequency applications is significantly affected by the microwave surface resistance (Rs). The paper delves into the basics, measuring methods and factors affecting the resistance (Rs) in YBCO, highlighting its high critical temperature (Tc) and low resistance, positioning it as a promising material. YBCO's compatibility with epitaxial growth and microstructure engineering offers opportunities to reduce grain boundary effects and improve Rs, making it advantageous for high-frequency electronics, communication systems, and MRI coils. This is due to its high critical current density (Jc) and exceptional Rs at practical temperatures. Challenges remain in comprehending and managing Rs in YBCO, despite its favorable characteristics. Utilizing advanced fabrication methods and incorporating nanotechnology allow for customization of YBCO-based devices. Multi-scale modeling and simulation are essential for guiding experimental work and understanding YBCO's performance in high-frequency settings. This study highlights the promise of YBCO for future high-frequency technologies and stresses the importance of more research to overcome hurdles and fully exploit its capabilities, potentially transforming superconducting devices for practical use.

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Microstructure and microwave surface resistance of YBaCuO thin films

Cited by 15 publications

References 8 publications

TlBaCaCuO-(2212) thin films on lanthanum aluminate and sapphire substrates for microwave filters

TlBaCaCuO-(2212) thin films on lanthanum aluminate and sapphire substrates for microwave filters

Thickness dependence ofJ_cfor YBCO thin films prepared by large-area pulsed laser deposition on CeO₂-buffered sapphire substrates

Review on Microwave Surface Resistance of High Temperature Superconductor Yttrium Barium Copper Oxide

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Microstructure and microwave surface resistance of YBaCuO thin films

Cited by 15 publications

References 8 publications

TlBaCaCuO-(2212) thin films on lanthanum aluminate and sapphire substrates for microwave filters

TlBaCaCuO-(2212) thin films on lanthanum aluminate and sapphire substrates for microwave filters

Thickness dependence ofJcfor YBCO thin films prepared by large-area pulsed laser deposition on CeO2-buffered sapphire substrates

Review on Microwave Surface Resistance of High Temperature Superconductor Yttrium Barium Copper Oxide

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Thickness dependence ofJ_cfor YBCO thin films prepared by large-area pulsed laser deposition on CeO₂-buffered sapphire substrates