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

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 $\Delta \approx 130K$. 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.

4 pages, 3 figures, 1 table

References in corpus (4)

• Thermodynamics of Spin S = 1/2 Antiferromagnetic Uniform and Alternating-Exchange Heisenberg Chains
• Thermodynamics and spin gap of the Heisenberg ladder calculated by the look-ahead Lanczos algorithm
• Electronic States and Magnetic Propertis of Edge-sharing Cu-O Chains
• Quantum Phase Transitions of a Square-Lattice Heisenberg Antiferromagnet with Two Kinds of Nearest-Neighbour Bonds: A High-Order Coupled-Cluster Treatment

Cited by in corpus (5)

• Quantum Magnetism in Minerals
• The spin gap in malachite Cu2(OH)2CO3 and its evolution under pressure
• Analytical Bethe Ansatz for open spin chains with soliton non preserving boundary conditions
• Spin excitations in the two-dimensional strongly coupled dimer system malachite
• Scattering matrix for a general gl(2) spin chain