Magnetic tunnelling in trilayers with radio-frequency sputtered barrier layers

We have prepared iron and thin films and trilayers by RF magnetron sputtering. The argon pressure during the process is found to have a significant influence on the microstructure and the coercivity of the Fe layers so that we could obtain trilayers with a spin-valve-like magnetic behaviour for thickness as thin as 9 Å. Perpendicular transport measurements of such junctions indicate tunnel behaviour with barrier heights close to 1.5 eV while the barrier width is consistently lower than the nominal thickness. Magnetoresistance of these samples reaches up to 1.1% at room temperature.