Magnetic interactions in a ferromagnetic honeycomb nanoscale network

The magnetic structure and magnetization process in a permalloy wire-based honeycomb network have been investigated by means of magnetic-force microscopy (MFM) and magnetoresistance measurement. The MFM measurements show the remanent magnetic structures to be governed by magnetic interaction similar to the ice rule, which provides a direct analogy between the present honeycomb network and an Ising system on a kagom\'e lattice. The magnetoresistance measurements reveal that this interaction also dominates the magnetization processes in the network. By decreasing the exchange energy at the vertices of the network, the ice-rule type of interaction causes a transition of the magnetization process in the network.