Conductivity Oscillations in Current-Induced Metastable States in   Low-Doped Manganite Single Crystals
  Deterministic oscillations of current-induced metastable resistivity in changing voltage have been detected in La$_{0.82}$Ca$_{0.18}$MnO$_3$ single crystals. At low temperatures, below the Curie point, application of specific bias procedures switches the crystal into metastable resistivity state characterized by appearance of pronounced reproducible and random structures in the voltage dependence of the differential conductivity. In certain bias range equally spaced broad conductivity peaks have been observed. The oscillating conductivity has been tentatively ascribed to resonances in a quantum well within the double tunnel barrier of intrinsic weak-links associated with twin-like defect boundaries. 
V. Dikovsky, Y. Yuzhelevski, V. Markovich, G. Gorodetsky, and G. Jung