Nonlinear electrical response in a charge/orbital orderedPr0.63Ca0.37MnO3crystal: The charge density wave analogy

Nonlinear conduction in a charge-ordered manganese oxide Pr 0 . 6 3 Ca 0 . 3 7 MnO 3 is reported. To interpret such a feature, it is usually proposed that a breakdown of the charge or orbitally ordered state is induced by the current. The system behaves in such a way that the bias current may generate metallic paths, giving rise to a resistivity drop. One can describe this feature by considering the coexistence of localized and delocalized electron states with independent paths of conduction. This situation is reminiscent of what occurs in charge-density-wave systems where a similar nonlinear conduction is also observed. In light of recent experimental results suggesting the development of charge density waves in charge and orbitally ordered manganese oxides, a phenomenological model for charge-density-wave motion is used to describe the nonlinear conduction in Pr 0 . 6 3 Ca 0 . 3 7 MnO 3 . In such a framework, the nonlinear conduction arises from the motion of the charge-density-wave condensate which carries a net electrical current.