Enhanced magnetocaloric effect in quasi-one-dimensional S = 1/2 Heisenberg antiferromagnet [Cu(dmen)2(H2O)]SiF6

• Low-dimensional magnetic behavior was found in [Cu(dmen)2(H2O)]SiF6.
• Enhanced magnetocaloric effect occurs at low enough temperatures (T ≪ J/kB).
• The isothermal change of entropy can be 20 times larger than that in paramagnet.

The results of specific heat and electron-spin resonance of [Cu(dmen)2(H2O)]SiF6 (dmen = N,N-dimethyl-1,2-diaminoethane) are reported. The studied material can be considered as an S = 1/2 quasi-one-dimensional Heisenberg antiferromagnet with dominant intrachain interaction Jintra/kB = −3.59 K. The appearance of both normal and inverse magnetocaloric effect in various field ranges below saturation field Bsat is tentatively attributed to weaker ferromagnetic interchain interactions. Pronounced magnetocaloric effect is found in the vicinity of Bsat, where at temperatures T ≪ |Jintra/kB|, the isothermal change of entropy was found to be about 20 times higher than that in S = 1/2 paramagnet. The potential origin of the observed behavior is discussed.

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