Size-dependent paramagnetic-ferromagnetic phase transition in palladium clusters

摘要

Ab initio calculations performed for T=0 K show that in palladium clusters below a critical size the high surface energy anisotropy stabilizes the icosahedral multiply twinned particle structure against the fee structure. Model calculations support the appearance of ferromagnetic order for the noncrystallographic icosahedral symmetry with a small (0.11 mu (B)) magnetic moment per atom. These results explain the recent experimental findings [Europhys. Lett. 38, 195 (1997)] that small free palladium clusters exhibit spontaneous ferromagnetic order. [References: 27]