Normal state interlayer conductivity in epitaxial Nd_2–xCe_xCuO₄ films deposited on SrTiO₃ (110) single crystal substrates

In this paper we present the experimental results on the temperature dependences of c-axis resistivity, ${\rho }_c$(T), for epitaxial films of n-type superconductor Nd_2–xCe_xCuO_4+δ deposited on (110) SrTiO₃ single crystal substrate in a wide range of Ce content from lightly to heavily substitution regions ($x=0.12-0.20$) under an optimal annealing. Alternative empirical models were used for a description of the observed semiconductor–like ${\rho }_c\left(T\right)$ dependence. An excellent quantitative depiction of the experimental ${\rho }_c\left(T\right)$ dependences turned out to be possible for all investigated samples in a model of natural superlattice with temperature - dependent barrier height. (paper)