Temperature independent leakage current in Au/TbMnO3/Y Ba2Cu3O7−x capacitors

Au/TbMnO3/Y Ba2Cu3O7−x capacitors were fabricated on LaAlO3 substrates and electrical characteristics were studied in the temperature range from 300 to 25 K. When temperature is higher than 225 K, Ohmic conduction is observed in the capacitors. Non-linear current–voltage characteristics are exhibited at low temperatures. Moreover, temperature-independent leakage currents are found at temperatures lower than 150 K. These electrical characteristics can be explained in terms of conduction transition originated from a thermal activation between 225 and 150 K, and the temperature-independent leakage currents are governed by the Poole–Frenkel emission and minor trap ionization energies.

► Au/TbMnO3/Y Ba2Cu3O7−x capacitors were fabricated.
► Temperature-independent leakage currents are observed.
► The electrical characteristics are explained in terms of conduction transition.
► Conduction transition is originated from a thermal activation.
► The leakage mechanism is governed by the Poole–Frenkel emission.