Bruneel, Els

De Keukeleere, Katrien

De Roo, Jonathan

Diez Sierra, Javier

Rijckaert, Hannes

Van Driessche, Isabel

English

Ghent University Academic Bibliography

XPS for evaluation of dopant distribution in YBCO thin films Els Bruneel, Hannes Rijckaert, Katrien De Keukeleere, Javier Diez Sierra, Jonathan De Roo, Isabel Van Driessche Department of Chemistry, Scripts, Ghent University, Krijgslaan 281 S3, 9000, Ghent, Belgium   Introduction Crystalline nanoparticles are used as active pinning centres in YBa2Cu3O7- (YBCO) thin films in order to improve the critical current density (Jc). Precursor solutions are deposited via chemical solution deposition on LaZrO3 or LaAlO3 substrates followed by a calcination and sintering process. During this process nanoparticles are either pushed to the YBCO surface, sink to the substrate interface or, as preferred, are homogeneously distributed throughout the superconducting film. XPS sputterprofiling was used to establish this distribution throughout the thin film.   Results and Discussion YBCO thin films of 400 till 800 nm are doped with different kinds of nanoparticles. The behaviour of these nanoparticles during the thermal process depends on their surface chemistry, size, growth rate and the YBCO precursor solution. For evaluation, films were sputtered with an Ar+ ion gun. After consecutive sputter cycles an area of 250 × 1000 µm2 was analysed (VG Surface Science Instruments). The step size was chosen after calibration versus a Ta2O5–reference thin film. Relative sputterrate of YBCO versus Ta2O5 could be determined as 2.67 (st dev 0.71) for calcined samples and 0.79 (st dev 0.15) for fully sintered films, fig. 1. The atomic composition after every sputter cycle is estimated using Casa XPS soft-ware. For visual representation of nanoparticle distribution the molar percentage of dopant versus yttrium concentration showed to be a useful tool. As such, distinction between homogeneous distribution, accumulation at the interface or at the sample surface could be distinguished.   Conclusions It is demonstrated that XPS sputter profiling can be used for the study of nanoparticle distribution in thin films.  References [1] H. Rijckaert et.al, Chemistry of materials, 2017, 29, 6104-6113 [2] K. De Keukeleere et. al., Advanced electronic materials, 2016, 2, 1600161                Fig. 1: Histogram of YBCO sputterrate versus Ta2O5       Fig. 2: La, Zr, La relative composition with increase of Zr concentration at the interface 

XPS for evaluation of dopant distribution in YBCO thin films

https://biblio.ugent.be/publication/8642416/file/8642431

XPS for evaluation of dopant distribution in YBCO thin films

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