Formation of $^3$He droplets in dilute $^3$He-$^4$He solid solutions*

We review the different stages of the formation of $^3$He droplets in dilute solid $^3$He-$^4$He solutions. The studies are interesting because the phase separation in isotopic helium mixtures is a first-order transition with a conserved order parameter. The rate of growth of the droplets as observed in NMR studies [1] is compared with the rates expected for homogeneous nucleation followed by a period of coarsening known as Ostwald ripening.\newline [1] C. Huan {\it et al.}, J. Low Temp. Phys. 162,167 (2011).