Regulation of Kasteleyn Transition in Macroscopic Square Ice by intra-unit interactions

To reveal the regulatory mechanism of magnetic interactions between magnets within a unit on the Kasteleyn transition between the antiferromagnetic phase and the Coulomb phase in the square ice model, and to address the research gap in real-time observation of phase transition dynamics in artificial spin ice systems, a square lattice containing hundreds of macroscopic magnets was constructed, which is termed “macroscopic square ice”.

The unit gap l was taken as a uniquely tunable geometric parameter, while the vertex gap d, another geometric parameter, was fixed to be 1.1 mm. The evolution of the proportions of three vertex types and domain areas was recorded in real time to analyze the order and transition characteristics of the macroscopic square ice. Experimental results show that when the unit gap l is larger than the vertex gap d, the proportion of type‑I vertices decreases monotonically with decreasing l from 97.22% to 84.35%, while the proportions of type‑II and type‑III vertices increase.