Exfoliated graphite and ozonated single-wall carbon nanotubes for encapsulation of the single-molecule magnet Mn12

Abstract We outline experiments on single-wall carbon nanotubes (SWNT) and exfoliated graphite (EG), as templates for producing nanostructures of the nanomagnetic manganese acetate cluster (Mn 12 [(CH 3 COO) 16 (H 2 O) 4 O 12 ] · 2CH 3 COOH · 4H 2 O),Mn 12 . Mn 12 grown in EG and SWNT exhibit downward shifts in its blocking temperature, ac susceptibility response and magnetic hysteresis loops. Temperature dependence of the magnetization reversal dynamics shows that encapsulation in EG or ozonated SWNT shortens the Arrhenius relaxation time for magnetization reversal, τ o , from 7.8 × 10 −8 to 1.4 × 10 −8 s, with a marginal lowering of the activation barrier from 68 ± 5 to 60 ± 5 K. The role of Mn–O modes in the magnetization dynamics together with these data indicate the potential for controlling Mn 12 properties via encapsulation.