Switching-probability distribution of spin-torque switching in MgO-based magnetic tunnel junctions

The time-evolution of the switching characteristics of spin-torque switching in MgO-based magnetic tunnel junctions (MTJs) during more than 10(9) write/read cycles was measured experimentally. In the measurements, the magnetic field and current conditions were chosen to give a switching probability (P(sw)) of about 0.5, where P(sw) is most sensitive to changes in the magnetic properties of an MTJ cell. Interestingly, some MTJ cells showed small jumps of P(sw), which can be attributed to random transitions between states with slightly different magnetic configurations. Such time-evolution measurement can be used to evaluate the stability of the switching characteristics of memory cells. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3637545]