LAUSR

In artificial spin ice systems, an interplay of defects and dipolar interactions is expected to play important roles in stabilizing different collective magnetic states. In this work, we investigated the magnetization reversal of individual defective square artificial spin ice vertices where defects break fourfold rotational symmetry of the system. By varying the angle between the applied field and the geometrical axis of individual vertices, we are able to access different energy landscapes of the system. Thus, we find a tuning parameter to stabilize different collective magnetic configurations of a defective vertex. Interesting among them is the collective low-energy state which is otherwise observed in a fully demagnetized state. Micromagnetic simulations are performed for the exact experimental conditions the results of which are consistent with the experimental data.