Magnetization reversal of elliptical Co/Cu/Co pseudo-spin valve dots

We present our recent simulated results on Cr (5 nm)/ Cu (5 nm)/ Co (5 nm)/ Cu (3 nm)/ Co (2 nm) pseudo-spin valve dots. The simulated results agree qualitatively with the experimental results. Three different sizes of elliptical dots, $150 nm×105 nm,$ $175 nm×70 nm,$ and $200 nm×60 nm,$ were simulated. Our simulations show that in these types of dots magnetization reversal occurs by the formation of domain walls: $90°$ for $175 nm×70 nm$ and $360°$ for $200 nm×60 nm.$ No domain wall was observed in the reversal of the $150 nm×105 nm$ dots. For such dots, the simulated loops show a small two-step reversal pattern with the thin upper layer partially reversing followed by complete reversal of both layers at higher fields. In the larger dots, a two-step reversal is clearly observed both in the simulation and experiment.