Melting and magnetic ordering in transition-metal microclusters

Abstract

Melting behavior of transition-metal clusters is studied by extensive Monte Carlo simulation for cluster sizes from N=7 to 17 atoms. Physical quantities such as internal energy, specific heat, bond-length average, and bond-length fluctuations are shown. A long-range magnetic interaction between spins assumed to be localized on the atoms is then included for the first time in melting studies. The interplay between magnetic and cohesive interactions is shown to give rise to interesting effects such as cluster volume contraction and sharper melting, as well as a magnetic transition at low temperature. Application to Ni, Co, and Fe clusters is discussed.