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arXiv · 0907.1230

Inelastic neutron scattering studies of the quantum frustrated magnet clinoatacamite, $γ$-Cu2(OD)3Cl, a proposed valence bond solid (VBS)

A. S. Wills·T. G. Perring·S. Raymond·B. Fak·J. -Y. Henry·M. Telling
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Abstract

The frustrated magnet clinoatacamite, $γ$-Cu$_2$(OH)$_3$Cl, is attracting a lot of interest after suggestions that at low temperature it forms an exotic quantum state termed a Valence Bond Solid (VBS) made from dimerised Cu$^{2+}$ ($S=1/2$) spins.\cite{Lee_clinoatacamite} Key to the arguments surrounding this proposal were suggestions that the kagomé planes in the magnetic pyrochlore lattice of clinoatacamite are only weakly coupled, causing the system to behave as a quasi-2-dimensional magnet. This was reasoned from the near 95$^\circ$ angles made at the bridging oxygens that mediate exchange between the Cu ions that link the kagomé planes. Recent work pointed out that this exchange model is inappropriate for $γ$-Cu$_2$(OH)$_3$Cl, where the oxygen is present as a $μ_3$-OH.\cite{Wills_JPC} Further, it used symmetry calculations and neutron powder diffraction to show that the low temperature magnetic structure ($T<6$ K) was canted and involved significant spin ordering on all the Cu$^{2+}$ spins, which is incompatible with the interpretation of simultaneous VBS and Néel ordering. Correspondingly, clinoatacamite is best considered a distorted pyrochlore magnet. In this report we show detailed inelastic neutron scattering spectra and revisit the responses of this frustrated quantum magnet.

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A. S. Wills, T. G. Perring, S. Raymond, B. Fak, J. -Y. Henry, M. Telling. 2009-07-07. Inelastic neutron scattering studies of the quantum frustrated magnet clinoatacamite, $γ$-Cu2(OD)3Cl, a proposed valence bond solid (VBS). https://doi.org/10.1088/1742-6596/145/1/012056

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