  The interplay between spin-orbit coupling (SOC) and electron correlation
($U$) is considered for many exotic phenomena in iridium oxides. We have
investigated the evolution of structural, magnetic and electronic properties in
pyrochlore iridate Y$_2$Ir$_{2-x}$Ru$_{x}$O$_7$ where the substitution of Ru
has been aimed to tune this interplay. The Ru substitution does not introduce
any structural phase transition, however, we do observe an evolution of lattice
parameters with the doping level $x$. X-ray photoemission spectroscopy (XPS)
study indicates Ru adopts charge state of Ru$^{4+}$ and replaces the Ir$^{4+}$
accordingly. Magnetization data reveal both the onset of magnetic
irreversibility and the magnetic moment decreases with progressive substitution
of Ru. These materials show non-equilibrium low temperature magnetic state as
revealed by magnetic relaxation data. Interestingly, we find magnetic
relaxation rate increases with substitution of Ru. The electrical resistivity
shows an insulating behavior in whole temperature range, however, resistivity
decreases with substitution of Ru. Nature of electronic conduction has been
found to follow power-law behavior for all the materials.
