Ag assisted evolution of ordered L10 CoPt alloy nanoparticles

► Influence of Ag additive on structural and magnetic properties of CoPt. ► Increasing Ag content results in tetragonal distortion of L10 CoPt phase. ► Ag particles are in contact with CoPt imparting surface strain. ► Enhancement in magnetic anisotropy on account of induced surface strain. ► Interesting feature of tunability between chemical ordering and coercivity may be useful for practical applications.