There is not a rule. The particle size could not change. Where is silver located in your lattice? Do you expect a variation of the lattice parameter? And why do you expect a variation of sizes? The doping could introduce a disorder, in some cases in an XRD pattern you can verify an increase of peak broadening so a reduction of crystallite sizes, but each sample is different from any other
Marcella Bini I am reducing the copper amount because of that the silver will locate in the position of some copper lattice. I thought that may be there will be a chance of change in the particle size slightly.