Magnetic tunnel junctions with yttrium oxide barrier

Abstract

Magnetic tunnel junctions have been studied, with YO x barriers prepared by plasmaoxidation of a 1.5 nm Y film. We report their junction area resistance, tunnel magnetoresistance(TMR) and barrier parameters (height and thickness) as a function of the oxidation time. For the optimum oxidation time, TMR values of ∼25% are obtained at room temperature and ∼44% at low temperature (5 K). The barrier height extracted from the current–voltage curves, is close to 1 eV, which is less than half of what is usually reported for AlO x -based junctions.Structural and topographical characterization of the multilayes revealed that the YO x layer is amorphous with well-defined, smooth, and correlated interfaces with the ferromagneticelectrodes.