X-ray photoelectron spectroscopy studies of electronic structure of Nd2−xCexCuO4−y and YBa2Cu3O7−y epitaxial film surfaces and resistive switchings in high temperature superconductor-based heterostructures

Bipolar effect of resistive switchings (BERS) in epitaxial film-based heterostructures Nd2−xCexCuO4−y and YBa2Cu3O7−y is investigated in the paper using the fundamental properties of the HTSC parent compounds - antiferromagnetic Mott insulators, which exhibiting a transition between a metal and an insulator owing to oxygen doping. The studies of electronic structure of the NCCO and YBCO epitaxial films surfaces by XPS and AFM have shown that the surface layer (∼30 nm) doped with oxygen is changing from metal (in a film bulk) to insulate state on the surface. The current-voltage characteristics of BERS devices obey a diode-like model upon the approach based on the double-diode equation.