Conduction mechanisms in epitaxial and polycrystalline SmNiO$_{3}$ thin films

Correlated oxides that exhibit metal-insulator phase transitions are emerging as potential candidates for switching devices and their fundamental physical properties are of interest. One such material is SmNiO$_{3}$, which has a transition temperature above room temperature ($\sim$400 K in bulk crystals). We present temperature- and bias-dependent conduction mechanisms in epitaxial and polycrystalline SmNiO$_{3}$ thin films. In both cases, at low electric field we observe thermally assisted hopping conduction through defect states. At high electric field the conduction transitions to a space-charge limited regime controlled by an exponential trap distribution. The trap decay parameter in epitaxial films does not have the expected 1/T temperature dependence, which may be a signature of band gap narrowing at high temperature due to the insulator to metal transition. The role of defects in affecting charge transport parameters will be discussed.