  A central feature of the Periodic Anderson Model is the competition between
antiferromagnetism, mediated by the Ruderman-Kittel-Kasuya-Yosida interaction
at small conduction electron-local electron hybridization $V$, and singlet
formation at large $V$. At zero temperature, and in dimension $d>1$, these two
phases are separated by a quantum critical point $V_c$. We use Quantum Monte
Carlo simulations to explore the effect of impurities which have a local
hybridization $V_{*} < V_c$ in the AF regime which are embedded in a bulk
singlet phase with $V > V_c$. We measure the suppression of singlet
correlations and the antiferromagnetic correlations which form around the
impurity, as well as the size of the resulting domain. Our calculations agree
qualitatively with NMR measurements in CeCoIn$_{5-x}$Cd$_x$.
