Modelling of frustrated twisted kagome spin-ice through direct calculation.

DyAgGe and its cousin compound, HoAgGe are two uniquely frustrated 2D spin-ice materials with a twisted Kagome lattice geometry which exhibit magnetic properties yet to be fully explained. In magnetic field, they exhibit step-like magnetization plateaus at simple fractions of the saturation magnetization. It is believed that this phenomenon results from strong single-site anisotropy, which in HoAgGe was found to be in-plane, forming a site-dependent Ising Hamiltonian and resulting in a two-dimensional spin-ice. In DyAgGe, our preliminary experimental results, as well as DFT calculations indicate that the easy axis is tilted away for the plane, this generating a site-dependent Potts model. Using more standard modeling techniques, such as Monte Carlo simulations, has proved to be very difficult for modeling systems exhibiting this level of frustration. However, using more novel computational methods, we have been able to reproduce many of the experimental features of both the HoAgGe and DyAgGe crystals. In this work we present a method to directly optimize the frustrated spin system through a Reduced Configuration Space search and present some preliminary results for the DyAgGe material.