GdBa 2 Cu 3 O 7 x -BaHfO 3 (GdBCO-BHO) nanocomposite (NC) films containing 12 mol% BHO nanoparticles were prepared by chemical solution deposition (CSD) following the TFA route on SrTiO 3 (STO) single crystals and buffered metallic tapes supplied by two different companies: Deutsche Nanoschicht GmbH and SuperOx. We optimized the preparation of our GdBCO-BHO solutions with acetylacetone making the film synthesis very robust and reproducible, and obtained 220 nm films with excellent superconducting properties. We show the structural, morphological and superconducting properties of the films after a careful optimization of the processing parameters (growth temperature, oxygen partial pressure and heating ramp). The films reach critical temperatures (T c ) of ∼94 K, self-field critical current densities (J c ) of >7 MA cm 2 and maximum pinning force densities (F p ) of ∼16 GN m 3 at 77 K on STO and T c of ∼94.5 K and J c > 1.5 MA cm 2 on buffered metallic tapes. The transport properties under applied magnetic fields are significantly improved with respect to the pristine GdBCO films. The GdBCO-BHO NC films on STO present epitaxial c-axis orientation with excellent out-of-plane and in-plane texture. The films are, in general, very dense with a low amount of pores and only superficial indentations. On the other hand, we present, for the first time, a systematic study of CSD-grown GdBCO-BHO NC films on buffered metallic tapes. We have used the optimized growth conditions for STO as a reference and identified some limitations on the film synthesis that should be overcome for further improvement of the films' superconducting properties.

Gd0.5Y0.5Ba2Cu3O7–x thin films have been grown from solutions of metal trifluoroacetates dissolved in methanol. These precursor solutions are well suited for chemical solution deposition because of their good wettability and long shelf lives. This could allow for high reproducibility of metalorganic decomposition and film growth if not counteracted by the highly hygroscopic nature of the solutions. Exposure to moist air can result in significant absorption of water with detrimental effects on microstructural film integrity, making the solutions and as-deposited films difficult to handle. To overcome this issue, acetylacetone (acac) has been introduced to the solutions as an additive. The complexing nature of this agent leads to strong interactions with the salts of Cu and the rare earth elements, reducing the sensitivity to humidity significantly. Films grown from acac-containing solutions are considerably smoother and denser, which in turn leads to enhanced current-carrying capabilities. To investigate the role of acac and its impact on the microstructure and superconducting properties of the films, infrared spectroscopy and thermogravimetry coupled with differential thermal analysis have been performed on different types of solutions and films with and without acac. The microstructural features of the films have been thoroughly compared by scanning electron microscopy. The superconducting properties, T c and J c, have been measured by inductive and resistive techniques. Particular focus has been put on the film characteristics that develop with varying amounts of moisture in the process gas during the decomposition of the metalorganic compounds.