Quasi‐two‐dimensional antiferromagnetism in Fe[S2CNC4H8]2I
| Autor: | R. V. Chamberlain, J. A. Lukin, Gary C. DeFotis, S. A. Friedberg |
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| Rok vydání: | 1993 |
| Předmět: | |
| Zdroj: | Journal of Applied Physics. 73:5654-5656 |
| ISSN: | 1089-7550 0021-8979 |
| DOI: | 10.1063/1.353629 |
| Popis: | Recent studies of the magnetic susceptibility of powdered Fe[S2CNC4H8]2I confirm that Fe(III) in this salt is in the unusual spin state S=3/2 and that the system behaves as a quasi‐2D antiferromagnet. Analysis of the data indicates that the ‖±1/2≳ ground doublet is separated by Δ/k=18.7 K from an excited ‖±3/2≳ doublet. We have now measured the heat capacity of polycrystalline Fe[S2CNC4H8]2I between 0.5 and 80 K in a liquid 3He‐cooled calorimeter. CP exhibits a λ‐type peak at TN=2.18±0.01 K. The critical entropy, S(TN)=0.25R ln2, indicates that most of the spin order is of a short‐range, low‐dimensional nature. The contribution of lattice vibrations to CP was estimated using the method of Sorai and Seki [J. Phys. Soc. Jpn. 32, 382 (1972)], which assumes a Schottky contribution from two doublets whose separation Δ was determined from the magnetic data. At the same time, the cooperative peak was reasonably represented by the results for the 2D S=1/2 XY model with Jxy/k=−2.18 K. In order to obtain a self‐con... |
| Databáze: | OpenAIRE |
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