Magnetic hollow cages with colossal moments.

A comprehensive study of the interaction of transition metal clusters with B, C, N, O, and Si reveal novel structure and properties: Co12C6, Mn12C6, and Mn24C18 clusters form stable ferromagnetic hollow cages with total magnetic moments of 14 μB, 38 μB, and 70 μB, respectively. Replacement of C with B, N, O, or Si has significant impact on their structure and magnetic properties. For example, Mn20Si12 cluster forms a ferrimagnetic dodecahedral hollow cage with a total magnetic moment of 36 μB while Mn12N6, X12C6 (X = Ni, Cu, Pd, Pt), and Cu12O6 possess no magnetic moment, although they retain hollow cage structures. Mn12B6 and Mn24Si18, on the other hand, form compact ferrimagnetic structures. Synthesis of hollow cage clusters with unique magnetic properties may lead to important applications.