Electric-field dependent conduction mechanisms in crystalline chromia

Abstract

We investigate mechanisms of electric-field-induced conduction in high-quality chromia crystals. A crossover is observed between space-charge limited conduction and the Frenkel-Poole mechanism with increasing temperature, with the crossover occurring in the vicinity of the Neel temperature of this material. From an analysis of the Frenkel-Poole conduction, we infer the presence of charge traps that lie approximately 0.5 eV below the conduction-band edge. Our experiments confirm the excellent dielectric properties of chromia, a result that is important for attempts to utilize this material as a "gate" dielectric in future spintronic devices.