Exchange-biased magnetic tunnel junctions with a CoFeB/MgO pinned layer, a Co free layer and an aluminum tris-(8-hydroxyquinoline) spacer layer of thickness ranging from 0–8 nm have been prepared by photolithography. The devices show a room-temperature, zero-bias magnetoresistance of 12.5±0.3%, which is unchanged after the crossover from tunneling to hopping transport at a barrier thickness of about 4 nm. The spin-diffusion length in the hopping regime is much greater than 10 nm. The magnetoresistance in the tunneling regime changes sign at a positive bias of 250 mV, and it is maximum at −100 mV.

Oriented c-axis films of the hexagonal triangular antiferromagnetic ε-Mn3Ga have been used in bottom-pinned synthetic antiferromagnet magnetic tunnel junctions with MgO barriers, which show up to 150% tunneling magnetoresistance at room temperature. Exchange bias fields as high as 150 mT can be achieved for samples field-cooled from 100 °C. Thin films of the antiferromagnet have a Néel temperature in excess of 650 K and provide an interface exchange energy with CoFe of 0.09 mJ m−2. They show an isotropic uncompensated magnetization of Ms = 48 kA m−1, with a coercivity μ0Hc > 3 T.

Single Co and Ta/Co bilayers were grown on Si͑100͒ substrates in a magnetron sputtering system. The effect of Ta buffer layer and the thickness of Co layer on the structural and magnetic properties of the Co layers has been studied. A single Co layer shows a textured structure above thickness of 40 nm according to the x-ray diffraction ͑XRD͒ pattern. The magnetic properties of Co layers depend significantly on the thickness of the films. Ta grows as highly textured ␤-Ta ͑tetragonal͒ phase on Si with a smooth surface. The XRD and atomic force microscopy results show that the Ta buffer layer improves the structural properties dramatically, resulting in a strongly textured and smoother surface morphology. The Ta layer also affects the magnetic properties of Co layers to a large extent, especially inducing an in-plane anisotropy in thin Co films.

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A method is described for measuring the magnetic integrity of ferromagnetic/organic interfaces that involves measuring the magnetic moment per unit area of bilayers with different ferromagnet thicknesses. The method is first used to determine the thickness of the oxide passivation layer on Co and Co90Fe10 (3.0 and 1.6 nm, respectively). The Alq3/Co interface is rather sharp, with roughness confined to about 3 monolayers of Co at the interface. The Co/Alq3 interface seems to be much rougher, with a dead layer that is several nanometers thick, However, this layer can be eliminated by capping the Alq3 layer with Al, so the dead layer is attributed to oxidation of the cobalt surface through the organic. The interface sharpness is improved when a 1 nm layer of LiF is inserted between Co and Alq3.