Characteristics of YBa₂Cu₃O₇ Thin Films Deposited on Substrates Buffered by Various TiO₂ Layers

Abstract

Titanium nitride (TiN) and superconducting YBa 2 Cu 3 O 7 (YBCO) thin films have been deposited sequentially on SrTiO 3 (STO)(100) substrates by in situ pulsed laser ablation. The TiN films were originally intended to serve as the lower contact electrode of the c-axis YBCO thin films. It was found that, although high-quality YBCO films could be obtained with the YBCO/TiN/STO(100) bilayer structure, the TiN(100) layer was oxidized which changed the structure into YBCO/TiO 2 /STO(100) during YBCO deposition. Comparative studies of depositing YBCO films directly onto a dc-sputtered TiO 2 /STO(100) template conventionally used in the selective epitaxial growth (SEG) process have, however, resulted in formation of a nonsuperconducting YBCO top layer. The characteristics of the resultant TiO 2 layers obtained using various processes were analyzed to delineate the apparent discrepancies.

Textured hydroxyapatite interface onto biomedical titanium‐based coatings

“…Furthermore, XRD diffractograms prove that at 800°C, the N substitution by O leads to the anatase TiO 2 phase. This behavior is similar to the one observed for SrTiO 3 /TiN/YBa 2 Cu 3 O 7 superconducting multilayer structures, which were found to fit better a SrTiO 3 /TiO 2 /YBa 2 Cu 3 O 7 composition, as deduced from chemical analysis 19. The diffusion of Ca and P can not be excluded from our AES depth profiles.…”

“…This behavior is similar to the one observed for SrTiO 3 /TiN/YBa 2 Cu 3 O 7 superconducting multilayer structures, which were found to fit better a SrTiO 3 /TiO 2 /YBa 2 Cu 3 O 7 composition, as deduced from chemical analysis. 19 The diffusion of Ca and P can not be excluded from our AES depth profiles. In fact, the temperature dependence of the diffusion into Ti alloys has been studied previously for HAP coatings deposited by pulsed laser deposition on Ti substrates.…”

Microstructure and magnetic properties of oxidized titanium nitride thin filmsin situgrown by pulsed laser deposition

“…Titanium dioxide (TiO 2 ) thin films have been studied and used extensively [1][2][3][4][5][6] since they possess remarkable optical, electronic, chemical and mechanical properties such as excellent optical transmittance (>85%) in the visible and near infrared wavelength ranges, high index of refraction (n ≈ 2.35 at 550 nm), large dielectric constant (ε r ≈ 105 at 4.2 K) and low loss tangent (tan δ ≈ 10 −7 at 4.2 K) [7,8], high chemical stability and mechanical durability. The widespread applications of TiO 2 films include (a) anti-reflecting and protective coating on optical elements; (b) capacitors or gates in microelectronic devices; (c) photocatalyst and catalytic devices; (d) optical waveguide in integrated optics and (e) suitable template layers for growing high-T c superconducting YBa 2 Cu 3 O 7 (YBCO) films, CrO 2 and LaSrMnO 3 films for microwave, biepitaxial junctions and spintronics applications [9][10][11].…”

Orthogonally Twinned CrO2(110) Epitaxial Films Grown on MgO(001) Substrates Buffered by Oxidized TiN

“…Recently, Liu et al demonstrated that CrO 2 can be grown on Si(001) substrates by using a TiO 2 (110) buffer layer, which is transformed from TiN(001) by thermal annealing in low-pressure oxygen. 7) Employing this oxidized TiN(001) buffer is unique method of obtaining TiO 2 thin films 8) and is indeed promising for increasing the possibility fof a device application for CrO 2 . Although Liu et al succeeded in demonstrating these oxidized buffer layers are suitable for CrO 2 growth, the details of the film quality as well as the epitaxial relationship between TiN and TiO 2 were not reported.…”