  The 3$d$-5$d$ based double perovskites are of current interest as they
provide model system to study the interplay between electronic correlation
($U$) and spin-orbit coupling (SOC). Here we report detailed structural,
magnetic and transport properties of doped double perovskite material
(Sr$_{1-x}$Y$_x$)$_2$FeIrO$_6$ with $x$ $\leq$ 0.2. With substitution of Y,
system retains its original crystal structure but structural parameters modify
with $x$ in nonmonotonic fashion. The magnetization data for Sr$_2$FeIrO$_6$
show antiferromagnetic type magnetic transition around 45 K, however, a close
inspection in data indicates a weak magnetic phase transition around 120 K. No
change of structural symmetry has been observed down to low temperature,
although the lattice parameters show sudden changes around the magnetic
transitions. Sr$_2$FeIrO$_6$ shows an insulating behavior over the whole
temperature range which yet does not change with Y substitution. Nature of
charge conduction is found to follow thermally activated Mott's variable range
hopping and power law behavior for parent and doped samples, respectively.
Interestingly, evolution of structural, magnetic and transport behavior in
(Sr$_{1-x}$Y$_x$)$_2$FeIrO$_6$ is observed to reverse with $x$ $>$ 0.1 which is
believed to arise due to change in transition metal ionic state.
