Structural and magnetic properties of CoRh nanoparticles

摘要: The structural and magnetic properties of free-standing ${\mathrm{Co}}_{n}{\mathrm{Rh}}_{m}$ clusters ($N=n+m\ensuremath{\approx}110$ $n\ensuremath{\approx}m$) three different symmetries\char22{}cubo-octahedral, icosahedral, hcp\char22{}were investigated in two chemical orders: segregated alternated layering alloyed. initial geometrical structures constructed at bulk distances were relaxed with a many-body Gupta potential to obtain the cluster geometries energies. We find that lowest energy all cases corresponds case (Rh-rich core surrounded by Co shells), is associated hcp structure. interatomic distance for slightly lower than Rh distance, good agreement experimental observation , [Zitoun et al., Phys. Rev. Lett. 89, 037203 (2002)]. spin-polarized electronic structure related these optimized calculated solving self-consistently $spd$ tight-binding Hamiltonian. moment atoms shows strong dependence on position environment, whereas show smoother dependence. (Co) alloying are larger (lower) ones case, however, overall average only structures. results compared data other theoretical calculations available literature.