Influence of Magnetostatic Interaction on the Magnetization Reversal of Patterned Co/Pd Multilayers Nanorings

We present a systematical investigation of magnetostatic interaction on magnetization reversal process for [Co(5 Å)/Pd(30 Å)]_n multilayers nanoring arrays separated by various edge-to-edge interring spacing (s). We observed that the coercivity H_c and switching field distribution (SFD) are strongly dependent on both s and number of multilayer repeats n. For a fixed n, the absolute SFD and both increase with increasing s. However, the normalized SFD (SFD/H_c) shows a non-monotonic variation, while a minimum value of the normalized SFD is observed at a critical s = 500 nm. The findings are strongly related to the magnetostatic interaction on magnetization reversal in nanoring arrays, which are further revealed by micromagnetic simulations together with magnetic force microscopy.