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In artificial square ice spin structures, the coupling strength between perpendicular mesospins is larger than between the collinear elements. Ideally one would like to be able to choose the asymmetry of the coupling strength, allowing the alteration of the obtained order and dynamics. In a previous study this was obtained by taking advantage of the change in interactions when shifting the orthogonal sublattices in the third dimension [1]. This approach was shown to successfully shift the asymmetry of the coupling strength, as judged from the amount of type-I and type-II vertices. An alternative way to change the asymmetry of the interaction is to introduce a circular magnetic island at each vertex [2]. A circular island made from 2DXY material is free to rotate in-plane and effectively act as a slave to the larger Ising like islands. This disc effectively increases the coupling strength between the collinear elements by mediating the interaction across the gap. By varying the disc diameter, one could thus tune the asymmetry of the coupling strength. Here, we describe the results of AC-susceptibility measurements of a modified square ice lattice and we compare the results to the dynamic properties of a square lattice. By measuring the response in the principal lattice directions we see how the symmetry of the interaction affects the dynamic properties of the structures.
[1] Yann Perrin et.al, Nature, 540(7633), 410
[2] Erik Östman et.al, Nature Physics, 14(4), 375.
