Measurement of magnetic moments of freeBiNMnMclusters

Magnetic properties of free ${\mathrm{Bi}}_{N}{\mathrm{Mn}}_{M}$ clusters ($N=2\char21{}20$, $M=0\char21{}7$) are determined from Stern-Gerlach deflections at low temperature $(46.5\phantom{\rule{0.3em}{0ex}}\mathrm{K})$. Pure bismuth clusters with odd number of atoms exhibit paramagnetic deflections. The addition of manganese atoms produces a ferromagnetic response which is strongly size dependent. Certain combinations have very large magnetic moments such as ${\mathrm{Bi}}_{5}{\mathrm{Mn}}_{3}$, ${\mathrm{Bi}}_{9}{\mathrm{Mn}}_{4}$, ${\mathrm{Bi}}_{10}{\mathrm{Mn}}_{5}$, and ${\mathrm{Bi}}_{12}{\mathrm{Mn}}_{6}$.