Modulated electric conductivity in Fe3O4/NiO superlattices

Abstract

High quality Fe3O4/NiO multilayered structures with nominal artificial periodicity 17 Å/ 17 Å and 34 Å/34 Å have been made by molecular beam epitaxy. The conductivity of the modulated structures is orders of magnitude higher for current parallel to the layers than for the transverse direction, reaching a ratio of 106−a value which is comparable with the largest known anisotropy for any material. This strong anisotropy shows that a like modulation of electrical conductivity has been achieved over distances as small as tens of Å and also suggests the possibility of voltage controlled superlattice phenomena.