High temperature superconducting thin films: correlation between properties and deposition parameters

In situ deposition of laser ablated YBaCuO thin films was performed on MgO single-crystal substrates using an excimer laser (KrF, 248 nm). Deposition and cooling steps were investigated in order to obtain c-oriented samples. In fact, the influence of the growth (substrate temperature, oxygen pressure, laser fluence) and post-deposition (nature, pressure) parameters on the structural (orientation, lattice parameters) and electrical (resistivity ρ at 300 K, critical temperature, transition width) properties were analysed. This study led to reproducible highly c-oriented samples which exhibit a critical temperature of 90 K, a superconducting transition width less than 1 K and a good metallic behavior (ρ300K/ρ100K ∼ 3). (orig.)