Quasi-Two-Dimensional Transport Properties
of the Layered Superconductor Nd_2xCe_xCuO₄₊

T. B. Charikova^a, A. I. Ponomarev^†a, G. I. Kharus^a, N. G. Shelushinina^a,
A. O. Tashlykov^a, A. V. Tkach^a, and A. A. Ivanov^b

^a Institute of Metal Physics, Ural Division, Russian Academy of Sciences, ul. S. Kovalevskoi 18, Yekaterinburg, 620041 Russia

e-mail: charikova@imp.uran.ru

^b Moscow Institute of Engineering Physics (State University), Kashirskoe sh. 31, Moscow, 115410 Russia

Received October 3, 2006

Abstract—The temperature dependences of resistivities _ab in the ab plane and _c along the c axis have been
studied for single-crystal Nd_2–xCe_xCuO₄₊ (x = 0.12, 0.15, 0.17, 0.20) films with (001) and orienta-
tions. The superconducting transition temperature and anisotropy coefficient are shown to be maximal in opti-
mally annealed samples (the oxygen content is close to the stoichiometric content, 0). A combination of
the metallic behavior of the _ab(T) dependence and the nonmetallic behavior of the _c(T) dependence for the
optimally annealed samples is an intrinsic property of the substance and an indication of the fact that the system
is quasi-two-dimensional. This layered quasi-two-dimensional system is an Anderson dielectric with a strongly
anisotropic localization radius ( ). An increase in the oxygen content and, hence, in the degree of
disorder in the Nd_2–xCe_xCuO₄₊ system is found to decrease the resistivity anisotropy coefficient. Thus, a dis-
order-induced Anderson transition takes place in this quasi-two-dimensional system.

PACS numbers: 72.15.Gd, 72.15Rn, 74.25.Ha, 74.72.Jt

DOI: 10.1134/S1063776107090208

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