Current-induced electroresistance in tetravalent cation-doped La0.9Hf0.1MnO3 epitaxial thin films

Influence of electric currents with a high density on the transport behavior of La0.9Hf0.1MnO3 thin films has been investigated in the absence of magnetic field. With different dc-currents from I = 0.5 mA (current density J = 1.0 × 103 A/cm2) to 25.0 mA (J = 4.8 × 104 A/cm2) applied on the sample, a striking observation is the significant decrease of the metal-insulator transition peak. The observed reduction ratio, the electroresistance ER = [R(0) − R(I)]/R(I) is ∼20%. This observation is similar to what we observed in other CMR systems like La1−xCaxMnO3 and La1−xBaxMnO3, indicating that the current-induced ER is a common feature for the CMR materials. The introduced new state is metastable and can be well repeated. Experiments revealed that it is not caused by oxygen deficiency. Although the nature behind such an effect has not been well understood yet, the observed ER effect seems to favor a percolative phase separation picture.