Pulsed-laser deposition of vicinal and c-axis oriented high temperature superconducting thin films

Pulsed-laser deposition (PLD) of high temperature superconducting Bi2Sr2Ca(n-1)CunOx, (Re,Hg)Ba2Ca(n-1)CunOx and YBa2Cu3Ox thin films on c-axis oriented and vicinal substrates is investigated. The optimization of the deposition parameters with respect to film crystallinity, electrical and superconducting properties and surface morphology is described. Based on the experience gathered, a new PLD facility was designed and constructed. Bi2Sr2Ca(n-1)CunOx films with n = 1, 2, 3 are deposited on SrTiO3 and MgO substrates. The n = 1 compound is deposited single phase and is also employed as buffer or top layer for Bi2Sr2CaCu2Ox thin films. Bi2Sr2CaCu2Ox films have been optimized with respect to their electrical, superconducting and morphological properties. On vicinal SrTiO3 substrates (10 degrees tilt angle) a series of films with thicknesses 20 to 300 nm are deposited. In-plane and out-of-plane resistivities and resistivity anisotropies are discussed. The substrate tilt angle was varied in the range 0 to 25 degrees. The influence of the substrate tilt angle on the film properties are investigated. Films revealed oriented growth for tilt angles up to 15 degrees and film thicknesses up to 300 nm. Single phase Pb-doped n 3 compound is deposited on MgO substrates. Deposition and post-annealing treatments are optimized with respect to the temperature, oxygen pressure and laser fluence. (Re,Hg)Ba2Ca(n-1)CunOx films are synthesized on (001) and vicinal SrTiO3 substrates in a two step process employing pulsed-laser deposition of Hg-free precursor films and Hg-vapour annealing in a sealed quartz tube. The sealed quartz tube technique is described in detail and the thermodynamics and the phase formation are discussed. The influence of the Hg-vapour pressure and the annealing temperature on the film properties are investigated. The influence of Hg-vapour annealing on Bi2Sr2CaCu2Ox films is described. YBa2Cu3Ox films with thicknesses 20 to 480 nm are deposited on vicinal SrTiO3 substrates (10 degrees tilt angle). Variation of the resistivities and changes in the film morphology depending on film thickness are described. The influence of post-annealing treatments on the film properties is discussed. (author)