Heavy and Light Monopoles in Magnetic Reversion in Artificial Spin Ice
  This work makes a theoretical study of the dynamics of emergent elemental excitations in artificial spin ice systems with hexagonal geometry during the magnetic reversion of the system. The magnetic and physical parameters of the nanoislands that form the array are considered as variables in the study. The parameters considered are: the energy barrier for the inversion of each nanoisland, the magnetic moment of the nanomagnets and the possible disorder in the sample. Our results show that the reversion dynamic presents two distinct mechanisms of magnetic reversion, with different elemental excitations for each mechanism. The first mechanism presents a reversion with the appearance of magnetic monopoles that do not move in the samples (heavy monopoles) and the absence of Dirac chains. In the other mechanism elemental magnetic excitations (light monopoles) appear that move great distances in the sample, giving rise to extensive Dirac chains during the magnetic reversion. 
Alejandro Leon
cond-mat.mes-hall