Current-induced switching in low resistance magnetic tunnel junctions

Current-induced magnetization switching (CIMS) in low resistance tunnel junctions is reported at critical current densities of 1.9×10⁶ A/cm² for tunnel junction areas ranging from 2 to 3 μm², and junction resistances from 6 to 20 Ω μm². Typical tunnel magnetic resistance values for these junctions range from 15% to 21% (measured in an external magnetic field) and 10% to 14% resistance changes are obtained by CIMS. Micromagnetic simulation indicates that vortex fields and spin transfer effects cannot fully account for the observed current-induced switching. Although able to explain the observed transition from a parallel or antiparallel state to a vortex state, it fails to explain the switch back to the original state, at a comparable but symmetrical critical current density. © 2003 American Institute of Physics.