A simple model for the size and shape dependent Curie temperature of freestanding Ni and Fe nanoparticles based on the average coordination number and atomic cohesive energy

► The Curie temperature (TC) of freestanding Ni and Fe nanoparticles have been examined. ► The average coordination number as a geometrical parameter has been considered. ► It is found that for even smaller particles, the Curie temperature actually increases.