Magnetic tunnel junctions with yttrium oxide barrier

Abstract

Magnetic tunnel junctions have been studied, with YOx barriers prepared by plasma oxidation 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 similar to25% are obtained at room temperature and similar to44% 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 AlOx-based junctions. Structural and topographical characterization of the multilayes revealed that the YOx layer is amorphous with well-defined, smooth, and correlated interfaces with the ferromagnetic electrodes. (C) 2003 American Institute of Physics.