Author/Authors :
M. Affronte، نويسنده , , R. Sessoli ، نويسنده , , D. Gatteschi، نويسنده , , W. Wernsdorfer، نويسنده , , J.C. Lasjaunias، نويسنده , , S.L. Heath، نويسنده , , A.K. Powell، نويسنده , , A. Fort، نويسنده , , A. Rettori، نويسنده ,
Abstract :
We report evidences for long-range antiferromagnetic (AF) order in iron oxyhydroxides Fe19metheidi and (enH2)2Fe6 clusters that at low temperature behave like single molecule magnets with total spin S=33/2 and S=5, respectively. Anomalies are clearly observed at 1.19 K in the heat capacity and in the low-field magnetization of Fe19metheidi while for (enH2)2Fe6 a broad λ-peak is found at 0.99 K in the heat capacity. Since dipolar interactions are estimated to be ∼190 mK and ∼40 mK for Fe19metheidi and (enH2)2Fe6, respectively, the origin of the AF ordering is due to super-exchange in these cases.
