New nanoparticles are provided which may have blocking temperatures exceeding 570 K even for particles as small as 8 nm in size. First principles theoretical investigations show that the new behavior is rooted in the giant magnetocrystalline anisotropies due to controlled mixing between carbon p-states and cobalt d-states. Furthermore, assemblies of the new nanoparticles may provide rare earth free permanent magnets having magnetic properties which rival those of rare earth permanent magnets.
