Superconducting properties of LuNi2B2C thin films

We present the results of collaboration between the groups of Naples and Ge noa Universities/INFM, focused on thin films superconducting borocarbides. In particular a careful study of the deposition of non-magnetic LuNi2B2C th in films by Pulsed Laser Deposition (PLD) on MgO and other substrates will be presented. While samples with good c-orientation and superconducting pro perties are obtained in a wide range of deposition parameters, in-plane mic rometric oriented structures are obtained only in a narrow range of conditi ons, as evidenced by X-rays measurements and AFM (atomic force microscopy) analyses. A special set-up for the in situ interchanging of shadow masks has been dev eloped in order to deposit the different patterned layers and different buf fer and/or barrier layers. New results on the temperature dependence of the LuNi2B2C gap using S/N contact junctions are presented and discussed. The obtained value of the superconducting gap and its temperature dependence ag rees very well with the BCS prediction. We present also microwave measurements of the surface impedance performed o n targe area films obtained by sputtering technique on low loss sapphire su bstrates. The data confirm the overall BCS-like behavior of these compounds .