Abstract
Current-induced switching from a metallic to an insulating state is observed in phase-separated states of () and () crystals. The application of magnetic fields to this current-induced insulating state causes a pronounced low-field negative magnetoresistance effect [ at ]. The application of a constant voltage also causes the breakdown of the Ohmic relation above a threshold voltage. At voltages higher than this threshold value, oscillations in currents are observed. This oscillation is well reproduced by a simple model of local switching of a percolative conduction path.
- Received 9 August 2004
DOI:https://doi.org/10.1103/PhysRevLett.94.157203
©2005 American Physical Society