Enhanced tunnel magnetoresistance in Fe-doped Al2O3 barriers

Abstract

It is shown that the tunnel magnetoresistance of a Co/Al2O3/Ni80Fe20 magnetic tunnel junction is enhanced by δ doping of the oxide barrier with Fe. Enhancements by a factor of up to 1.25 are observed for Fe layers less than a monolayer thick, positioned halfway in the Al2O3 insulator. The effect exists not only at low temperature, but persists up to room temperature, albeit slightly weakened. Also, the enhancement remains present under the application of voltages as large as 0.6 V. Possible explanations are discussed.