Using a tight-binding model with electron-electron interactions we sho
w that the magnetic states of 4d transition metal clusters are stabili
zed by the Hund's rule exchange interaction. Taking realistic paramete
rs we obtained magnetic states for Pd-13, Rh-13 and Ru-13 clusters whi
ch agrees qualitatively with the recent experimental data and with oth
er calculations. The interatomic distances increase by up to similar t
o 7% between nonmagnetic and magnetic clusters.