CPP transport properties of polycrystalline Fe ₃O ₄ thin films sputtered on Cu underlayers

Transport properties of sputtered Fe3 O4 thin films have been studied with the current perpendicular to plane (CPP) configuration. Fabricated polycrystalline Fe3 O4 films exhibit superior CPP conductivity of 12 k Ω-1 · m-1. In addition to the Verwey transition (VT), observed at 114 K, another type of drastic conductivity change [field induced transition (FT)] was observed at lower temperature (T<70 K) and higher bias voltage (Vb ≥0.18 V) regime. The conductivity change at FT is discontinuous and several orders in magnitude. The transition temperature for FT presents considerable Vb dependence, contrarily no distinguished dependence for VT.