Spin correlation in kagom\'{e} ice state: neutron scattering study of   the dipolar spin ice Dy_{2}Ti_{2}O_{7} under magnetic field along [111]
  We have investigated the kagom\'{e} ice state in the frustrated pyrochlore oxide Dy_{2}Ti_{2}O_{7} under magnetic field along a [111] axis. Spin correlations have been measured by neutron scattering and analyzed by Monte-Carlo simulation. The kagom\'{e} ice state, which has a non-vanishing residual entropy well established for the nearest-neighbor spin ice model by the exact solution, has been proved to be realized in the dipolar-interacting spin ice Dy_{2}Ti_{2}O_{7} by observing the characteristic spin correlations. The simulation shows that the long-range interaction gives rise to only weak lifting of the ground state degeneracy and that the system freezes within the degenerate kagom\'{e} ice manifold . 
Y. Tabata, H. Kadowaki, K. Matsuhira, Z. Hiroi, N. Aso, E. Ressouche,   B. Fak