Biaxially textured LuNi2B2C thin films on MgO single crystals

Biaxially textured LuNi2B2C thin films with high Tc up to 15.8 K and a residual resistivity ratio up to 15 have been prepared on MgO(1 1 0) substrates using pulsed laser deposition from a stoichiometric target. Via the precise control of the deposition rate, a biaxial texture is favored within a broad range of deposition temperatures, with an epitaxial relationship between the borocarbide film, the Lu2O3 interface layer and the substrate of (0 1 1)[0 0 1]MgO || (0 1 1)[0 0 1]Lu2O3 || (0 0 1)[1 0 0]LuNi2B2C. A very sharp in-plane alignment of about 1 ° and an out-of-plane order of about 2.5 ° was achieved in the LuNi2B2C layer. It is shown that the temperature is crucial for phase formation and superconducting properties. Applying optimized deposition conditions, critical temperatures of up to 15.8 K and steep superconducting transitions of about 0.3 K are reproducibly obtained. The upper critical field Hc2 of the optimized films was resistively measured along the [0 0 1] direction and fitted with a power law. The resulting value of Hc2(0) = 9.82 T is in very good agreement with single crystal data, whereas the power exponent describing the positive curvature for small external magnetic fields α = 0.19 indicates a relatively low intraband scattering in the films.