Relation between critical current of domain wall motion and wire dimension in perpendicularly magnetized Co/Ni nanowires

We investigated the relation between critical current of domain wall motion and wire dimension by using perpendicularly magnetized Co/Ni nanowires with different widths and thicknesses. The critical current, I(c), became less than 0.2 mA when w < 100 nm, suggesting that magnetic random access memory with domain wall motion can replace conventional embedded memories. In addition, in agreement with theory, the critical current density, j(c), decreased as wire width decreased and became much less than 5 x 10(7) A/cm(2) when w < 100 nm. We also performed a micromagnetic simulation and obtained good agreement between the experiment and simulation, although a few discrepancies were found. (C) 2009 American Institute of Physics. [doi: 10.1063/1.3271827]