Muon spin relaxation measurements of CsC60, RbC60, KC60

Muon spin relaxation (μ+SR) measurements of CsC60 and RbC60 have revealed magnetic ordering at 20 K and 15 K respectively, with static internal fields at the muon site of \sim7 G for both samples. No magnetic ordering is seen in KC60 down to 2.5 K. An apparent small increase in muon spin relaxation which had been seen at 70 K in RbC60 is ascribed to an extrinsic effect, originating in muons which stopped in the aluminum sample holder.