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Experimental evidence for a spin gap in the s=1/2 quantum antiferromagnet Cu$_2$(OH)$_2$CO$_3$

E. Janod·L. Leonyuk·V. Maltsev
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Abstract

Magnetic properties of the natural mineral Cu$_2$(OH)$_2$CO$_3$ (malachite) were investigated through DC and AC susceptibility measurements. The analysis of the low-temperature part reveals a quantum spin-gap behavior with $Δ\approx 130 K$. Consistently with the crystal structure, the magnetic susceptibility can be accurately described by a model of alternating chain. The non-frustrating residual inter-chain magnetic couplings, describing a sort of dimerized square planar lattice, are not strong enough to push the system towards a long-range ordered ground state, in good agreement with recent theoretical studies.

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E. Janod, L. Leonyuk, V. Maltsev. 2000-09-04. Experimental evidence for a spin gap in the s=1/2 quantum antiferromagnet Cu$_2$(OH)$_2$CO$_3$. https://doi.org/10.1016/s0038-1098(00)00365-3

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