Liquidlike correlations in single-crystalline Y$_2$Mo$_2$O$_7$: An unconventional spin glass

摘要: The spin-glass behavior of YMoO has remained a puzzle for nearly three decades. Free of bulk disorder within the resolution of powder diffraction methods, it is thought that this material is a rare realization of a spin glass resulting from weak disorder such as bond disorder or local lattice distortions. Here we report on the single-crystal growth of YMoO. Using neutron scattering, we present isotropic magnetic diffuse scattering occurring below the spin-glass transition. Our attempts to model the diffuse scattering using a computationally exhaustive search of a class of simple spin Hamiltonians show no agreement with the experimentally observed energy-integrated (diffuse) neutron scattering. This suggests that spin degrees of freedom are insufficient to describe this system. Indeed, a temperature dependence in the heat capacity and density functional theory calculations hint at the presence of a significant …