Reproducible formation of single magnetic bubbles in an array of patterned dots

The formation conditions of single magnetic bubbles through in-plane field demagnetization are investigated in an array of Co/Ni circular dots by magnetic force microscopy and compared to micromagnetic calculations. We demonstrate high success rates in nucleating stable bubbles. The efficiency of single bubble formation is found to depend not only on the dot size, material thickness and intrinsic material parameters but also on the bubble nucleation path. Experimental phase diagrams and micromagnetic calculations highlight the influence of the starting in-plane field amplitude and dipolar interactions in stabilizing the bubble. The identification of a systematic procedure for controlling nucleation of single bubbles, multidomain states or a uniform state is important from a technological point of view, opening a path toward the realization of reprogrammable magnonic crystals for the control of spinwave propagation.