Magnetotransport in exchange-coupled magnetite junctions

Epitaxial magnetic junctions of theoretically half-metallic electrode material magnetite were fabricated with a cobalt chromite paramagnetic insulating tunnel barrier. This spinel structure barrier was chosen to be isostructural to the magnetite electrodes. Highly crystalline trilayers with low surface roughness were grown. Strong exchange coupling between the electrodes is observed across the barrier. Magnetoresistance measurements are reminiscent of a single ferromagnetic layer and not a junction.