Large inverse magnetoresistance in fully epitaxial Fe/Fe3O4/MgO/Co magnetic tunnel junctions

Fully epitaxial Fe(001)/Fe3O4(001)/MgO(001)/Co micron-sized magnetic tunnel junctions have been elaborated on MgO(001) substrates. X-ray reflectivity and high-resolution transmission electron microscopy revealed a good quality and epitaxial growth of the stack with abrupt interfaces. The magnetotransport measurements exhibit a large negative tunneling magnetoresistance (TMR) value for magnetic tunnel junctions including an Fe3O4 layer and a MgO tunnel barrier (-8.5% at 300 K and -22% at 80 K). Moreover, the sign of the TMR changes with the applied bias. We discuss here the structural quality of the samples and the transport measurement results. (c) 2008 American Institute of Physics.