Prof. Junyi Ge’s group of Materials Genome Institute has created a tunable and switchable magnetic dipole patterns in nanostructured superconductors, which shed light on the study of artificial ice systems. The research was recently published in the prestigious journal Nature Communications.
Design and manipulation of magnetic moment arrays have been at the focus of studying the interesting cooperative physical phenomena in various magnetic systems.  However, long-range ordered magnetic moments are rather difficult to achieve due to the excited states arising from the relatively weak exchange interactions between the localized moments. By using a nanostructured superconductor, Prof. Junyi Ge et al. investigate a perfectly ordered magnetic dipole pattern with the magnetic poles having the same distribution as the magnetic charges in an artificial  spin ice. The key advantage of such a design is that the magnetic states can simply be switched on/off by applying a current flowing through nanopatterned area. Moreover, by coupling the magnetic dipoles with the pinned vortex lattice, the authors are even able to erase the positive/negative poles, resulting in a magnetic dipole pattern of only one polarity, analogous to the recently predicted vortex ice. These switchable and tunable magnetic dipole patterns open new ways for the study of exotic ordering phenomenona in magnetic systems.
The work was done with the collaboration of Prof. Victor V. Moshchalkov’s group from KU Leuven and Prof. Jacques Tempere’s group from University of Antewerp. 

J.-Y. Ge et al., Nature Communications 9, 2576 (2018).
URL：https://www.nature.com/articles/s41467-018-05045-3.