Photo-Assisted MOCVD Fabrication of YBCO Thick Films and Buffer Layers on Flexible Metal Substrates for Wire Applications

Abstract

Photo-assisted MOCVD has been developed for application to high-rate, high quality YBa 2 Cu 3 O 7−δ thin film production. This technique is now being applied to the fabrication of thick film YBa 2 Cu 3 O 7−δ on flexible metal substrates for wires and tapes. The unique application of photo-irradiation as the sole source of energy for the MOCVD reaction has resulted in extremely rapid growth rates for YBCO films with accompanying high superconducting performance. Typical YBCO films of thickness > 1 µm exhibit Jc ≥ 1 × 10 6 A/cm 2 and Tc > 90 K on single crystal oxide substrates. Such films have now been integrated to metal substrates such as single crystal Ni(100) and roll-textured nickel foil. YBCO films grown on textured Ni foils with CeO 2 and YSZ buffer layers show Jc ≈ 3 to 5 × 10 5 A/cm 2 for films of 1 µm thickness grown in 2 to 4 minutes time. Such performance for thick films made in such short growth time is promising for YBCO wire fabrication. The development of effective YBCO wire through thick film growth on flexible substrates also requires buffer layer application. Photo-assisted MOCVD has also been applied to buffer layer formation with promising results.

High-rate deposition of YBa2Cu3O7−δhigh-temperature superconducting films by IR-laser-assisted chemical vapor deposition

“…Although a group at the University of Houston developed a photo-assisted CVD process with a tungsten halogen lamp [13] and achieved a high rate of 42 µm h −1 [13], the film was a-axis-oriented, and J c ∼ 0.1 MA cm −2 . They also reported high-rate deposition of c-axis-oriented films [18][19][20][21][22][23]. However, the highest rate to yield high J c performance (more than 1 MA cm −2 ) was 12 µm h −1 [22,23].…”

Chemical Vapor Deposition of Cerium Oxide Films from a Cerium Alkoxide Precursor

“…We also report the synthesis and crystal structures of Ce(OCMe 2 - i -Pr) 4 (DMAP) 2 (DMAP = 4-(dimethylamino)pyridine) and Ce 2 (OCMe 2 - i -Pr) 5 (acac) 3 , and the crystal structure of the parent compound Ce(OCMe 2 - i -Pr) 4 . Previous studies on the CVD of cerium oxide films have used primarily β-diketonate complexes (e.g., Ce[ t -BuC(O)CHC(O)- t -Bu] 4 ), derivatives of β-diketonate complexes (e.g., Ce[(CF 3 C(O)CHC(O)CF 3 )] 3 (MeOCH 2 CH 2 OMe), and complexes with ligands that are closely related to β-diketonates as precursors. − There is one previous report on the attempted use of cerium alkoxide complexes as CVD precursors. In that study, Hubert-Pfalzgraf et al produced as-deposited films containing a mixture of ceria and cerium(III) fluoride from the fluorinated alkoxide compounds Ce[OCH(CF 3 ) 2 ] 4 (Me 2 NCH 2 CH 2 NMe 2 ) and Ce[OCH(CF 3 ) 2 ] 4 [Me(OCH 2 CH 2 ) 2 OMe) …”

MOCVD of LaMnO3 on Biaxially Textured Ni‐based Substrates in a Reducing Atmosphere

“…Only such P(O 2 ) enables the growth of complex oxides directly, without oxidation, on metal substrates such as nickel. [15,16] This limitation is not too severe. Thermodynamic estimations clearly show that perovskite chromates and manganites of rare earth elements could be formed on the surface of nickel without oxidation of the latter.…”