Transport Properties of Over-doped Epitaxial NdCeCuO Films

The transport properties of slightly overdoped Nd 2-xCe xCuO 4-δ (NCCO) c-axis oriented thin films with x = 0.17 have been investigated in the temperature range from 2.5 K to 300 K and in magnetic fields up to 6 T applied perpendicular to the CuO 2 planes. The films have been grown by a dc sputtering technique in on-axis configuration. They have been optimized on (001)-oriented SrTiO 3 substrates and successively annealed in pure Argon at 900 °C. Structural and compositional analyses were carried out by means of X-ray diffraction and scanning electron microscopy equipped with a wavelength dispersive spectroscopy detector. Current-voltage characteristics of the NCCO films have been measured and the temperature and the magnetic field dependence of the critical current density J c(T, H) has been obtained. Finally, an increase of the lowtemperature normal state resistance with the field has also been observed.