Surface magnon specific heat of ferromagnetic nanoparticles at low temperatures

Abstract Ferromagnetic nanoparticles have been explored to exhibit different magnetic properties from bulk materials at low temperatures. The surface effect is revealed to induce an enhancement in the magnon specific heat due to a higher surface spin magnetic moment with respect to the volume counterparts. An analytical expression is thus deduced that the surface magnon specific heat follows a T 5/4 law in ferromagnetic nanoparticles at low temperatures. This finding contributes to further our understanding of the novel structure and properties of ferromagnetic nanoparticles.