Dynamic dipolar interaction effect on spin-transfer switching with perpendicular anisotropy

Micromagnetic simulation is employed to study the influence of neighboring cells on spin torque switching in a matrix of nanopillars with perpendicular magnetic anisotropy. We find that with the decreased separation the critical switching current densities can be strongly modified for different matrix configurations as compared to an isolated disk element. Such variations are attributed to the stray fields rather than the resonant effect, although both of them arise from the dipolar interaction between the target and neighboring cells. The Bloch wall mediated switching process is evidenced by the magnetization snapshots, which agrees with the recent experimental results.