J Supercond Nov Magn (2017) 30:2401–2428 DOI 10.1007/s10948-017-4027-3 ORIGINAL PAPER Pulsed Laser Deposition of YBa 2 Cu 3 O x with Scanning Beam: Target to Substrate Composition Transfer and Film Structure Peter B. Mozhaev 1,2 · Alexey V. Khoryushin 2 · Julia E. Mozhaeva 1,2 · Jean-Claude Grivel 3 · Jørn Bindslev Hansen 2 · Claus S. Jacobsen 2 Received: 16 February 2017 / Accepted: 21 February 2017 / Published online: 18 March 2017 © Springer Science+Business Media New York 2017 Abstract Pulsed laser deposition is often considered a pro- cess providing congruent transfer of target composition to the growing film. In fact, many different processes affect compositional preservation, starting from incongruent tar- get ablation, to scattering on the way to the substrate, and to processes of the film formation on the substrate surface. We developed a pulsed laser deposition process trying to minimize the compositional deviations due to the scattering by the ambient gas by applying laser beam scanning across the target surface and substitution of oxygen with argon in the chamber during deposition. Transfer of elemental com- position of YBa 2 Cu 3 O 7 targets with compositions varying from stoichiometric 1/2/3 ratio was tested by deposition of thin films in conditions optimal for high-temperature super- conductor formation. Despite all measures, the films still show Ba,Y enrichment due to different efficiencies of scat- tering on the ambient gas. The Y part in the film followed well the composition of the target, but the Ba enrichment was almost constant for most of the studied target composi- tions, implying a crucial role of the film growth processes. The YBa 2 Cu 3 O x (YBCO) films show a layered structure, with increased density of defects in the topmost layer. We  Peter B. Mozhaev pbmozh@gmail.com 1 Institute of Physics and Technology RAS, Nakhimovsky Ave. 34, 117218 Moscow, Russian Federation 2 Department of Physics, Technical University of Denmark, 2800 Kongens Lyngby, Denmark 3 Department of Energy, Technical University of Denmark, Risø Campus, 4000 Roskilde, Denmark suppose this is due to expelling of the excess Ba into the top layer with formation of a quasi-liquid layer promoting formation of a high-density YBCO film. Keywords Pulsed laser deposition · Element composition transfer · YBa 2 Cu 3 O x · Thin film structure · Elements segregation 1 Introduction Pulsed laser deposition (PLD) is often considered a tech- nique with uniform transfer of elemental composition of the target to the substrate, but this assumption is disproved by numerous observations (a list of examples for different multicomponent materials can be found, e.g., in [1]). The elemental composition of the deposited material deviates from the composition in the target both during ablation, on the way from target to substrate, and due to processes on the substrate surface during film growth. A brief review of the reasons for film-target compositional deviation may be found in [2]. At the same time, a precise knowledge of the elemental composition of the film is necessary when addi- tion of excess material changes the properties of the result- ing film. As an example, incorporation of excess material in YBa 2 Cu 3 O x (YBCO) high-temperature superconductor may result in the formation of defects with a significant improvement of the current-carrying capabilities, namely, the critical current density. The same defects, though, are a source of noise when supercurrent passes a grain-boundary Josephson junction and suppress a reproducibility of prop- erties of such junctions. With no ambition of presenting a comprehensive review, we still would like to discuss briefly the main features of the pulsed laser deposition process and the way they influence