High T c superconducting thin films by rapid thermal annealing of Cu/BaO/Y2O3 layered structures

Abstract

Superconducting thin films of YBaCuO have been formed using rapid thermal annealing of Cu/BaO/Y2 O3 layered structures, which were deposited on MgO substrates by electron beam evaporation. The best film has an onset temperature of 94 K and zero resistance at 84 K. The dependence of the film characteristics and superconducting transition temperature on the annealing conditions has been studied. Auger depth profiling was used to examine the interdiffusion between the film and the MgO substrate.

Enhancement in superconducting properties of Y-Ba-Cu-O thin films by post-annealing in an inert atmosphere

“…From the results of our study, we can show that post-annealing in an inert atmosphere contributes to the good quality of superconducting thin films, which was also found by Ma et al [12] and Ra et al [9]. Davidson et al [11] reported that they obtained superconducting film with Tc ..... = 30 K through slow heating and slow cooling in an oxygen atmosphere; however, they could obtain 80 K as a Tc ..... from the same sample by rapid heating and slow cooling in a helium atmosphere.…”

“…The reason for employing rapid thermal annealing and a short heating time is that short annealing time is considered to be sufficient for crystallization of thin films and improved properties are expected due to the reduction of interdiffusion (interaction) between film and substrate. Several optimistic results on rapid heating effects have been reported [11][12][13]. In this paper, a comparison of heating rates, and the effects of annealing atmosphere on the characteristics of thin films are reported.…”

Defect phenomena in superconducting oxides and analogous ceramic oxides

“…Rutherford backscatter (Nakajima el a / 1988) h a s been used to look at the diffusivity of Cu in MgO, alumina, quartz, and Si substrates (where Cu moves faster than Y or Ba) and also to study the motion of substrate elements (hlg, Si, AI) in YBCO. They concluded that big0 seems the most stable, although other workers (Sugita et al 1988) suggest that small Mg/Cu interchange from the MgO substrate during annealing leads to a reduction in critical temperature; their samples showed variable range hopping corresponding to 0.5 states eV-'/cell below 100 K. Auger depth profiling has also been exploited to look for interdiffusion between a thin superconducting film of YBCO and the hlg0 substrate (Ma et al 1988). One would expect that a decrease in the synthesis temperature for thin films would reduce the interdiffusion between the film and the substrate, and this is observed (Wasa et a / 1988).…”

Accelerated growth by flash heating of high critical current trifluoroacetate solution derived epitaxial superconducting YBa2Cu3O7 films

“…This is the first time, to our knowledge, that such a phenomenon is clearly demonstrated in the growth of CSD complex multicomponent thin films, although the use of rapid thermal annealing in CSD film growth has already been demonstrated to have many advantages. [19][20][21][22] In addition to shortening the required processing time for film growth, the growth temperature of YBCO films has been reduced as well, the final film homogeneity is improved and the superconducting performances were enhanced due to a more favorable nanoscale structure. Particularly, we show that FH YBCO films have a high concentration of YBa 2 Cu 4 O 8 (Y248) intergrowths.…”