Defect-induced short-range-order from a spin-ice related state in deformed pyrochlore Co2 (OH)3 Cl

Recently, we observed a kagome-ice-like partial ferromagnetic order with coexisting fluctuation in a deformed pyrochlore structure Co2 (OH)3 Cl. Here, we show that when lattice defects are present, the remaining fluctuating spins in this material further freeze at lower temperatures below T< Tg =4 K after it initially freezes into the partial ferromagnetic order near TC =10 K. This low-temperature transition is glasslike requiring an extremely slow relaxation process in Co2 (OH)3 Cl. Enhanced disorder in (Co1-x Alx) 2 (OH)3 Cl leads to a short-range order for the fluctuating spins. This result can be considered as an interesting analogy to the low-temperature anomaly in defect-containing pure and doped water ice, especially in the light of its relevance to the problem of residual entropy in ice-water or spin-ice transition.