1201.5419 (M. C. Shapiro et al.)

Structure and Magnetic Properties of the Pyrochlore Iridate Y2Ir2O7    [PDF]

M. C. Shapiro, S. C. Riggs, M. B. Stone, C. R. de la Cruz, S. Chi, A. A. Podlesnyak, I. R. Fisher

Neutron powder diffraction and inelastic measurements were performed
examining the 5d pyrochlore Y$_2$Ir$_2$O$_7$. Temperature dependent
measurements were performed between 3.4 K and 290 K, spanning the magnetic
transition at 155 K. No sign of any structural or disorder induced phase
transition was observed over the entire temperature range. In addition, no sign
of magnetic long-range order was observed to within the sensitivity of the
instrumentation. These measurements do not rule out long range magnetic order,
but the neutron powder diffraction structural refinements do put an upper bound
for the ordered iridium moment of $\sim$ 0.2 $\mu_B /$Ir (for a magnetic
structure with wave vector $Q \neq 0$) or $\sim$ 0.5 $\mu_B /$Ir (for Q = 0).

View original: http://arxiv.org/abs/1201.5419