  A metal-encapsulating silicon fullerene, Eu@Si20, has been predicted by
density functional theory to be by far the most stable fullerene-like silicon
structure. The Eu@Si20 structure is a dodecahedron with D2h symmetry in which
the europium atom occupies the center site. The calculated results show that
the europium atom has a large magnetic moment of nearly 7.0 Bohr magnetons. In
addition, it was found that a stable "pearl necklace" nanowire, constructed by
concatenating a series of Eu@Si20 units, with the central europium atom,
retains the high spin moment. The magnetic structure of the nanowire indicates
potential applications in the fields of spintronics and high-density magnetic
storage.
