  We report the magnetic and thermal properties of Dy2Sn2-xSbxO7+x/2, x = 0,
0.25, and 0.5, and Dy2NbScO7. We find evidence for Ising-like single ion ground
states in the Dy2Sn2-xSbxO7+x/2 materials. These materials possess nearly the
same zero point entropy as the canonical spin ices Ho2Ti2O7 and Dy2Ti2O7,
strongly suggesting that they have spin ice states at low temperatures. We also
observe a somewhat reduced zero point entropy in Dy2NbScO7, which is possibly
associated with the higher level of cation disorder. The ice-like states in
these materials with cation disorder on the B-sites of the pyrochlore lattice
provide new evidence for the robust nature of spin ice behavior in the presence
of disorder.
