Growth and investigation of oxide heterostructures based on half-metallic Fe3O4

Abstract

We report thin films of ferromagnetic Fe3O4 (magnetite) grown by a reactive magnetron sputtering at T = 300 divided by 450degreesC on lattice-matched MgO, and bilayer structures composed of Fe3O4 and underlying epitaxial films of highly conductive electron-doped In2O3<Sn>, LaNiO3, and antiferromagnetic CoO. The prepared Fe3O4/MgO films and the bilayer structures demonstrated clearly defined resistance anomaly at Verwey transition point (T-V approximate to 100-120 K). Formation of high resistance interlayer was indicated between the adjacent conducting Fe3O4 and LaNiO3 layers. However, relatively low interface resistivity of about 0.1 Omega cm(2) (at T = 300 K) was estimated for the patterned Fe3O4/In2O3(Sn) bilayer structures. Vertical electrical transport measurements revealed strong nonlinearity in the I-U dependences of the Fe3O4/In2O3<Sn> interface at T < T-V.