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Approaching the ground state of the kagome antiferromagnet

W. Schweika·M. Valldor·P. Lemmens
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Abstract

Y{0.5}$Ca{0.5}BaCo4O7 contains kagome layers of Co ions, whose spins are strongly coupled according to a Curie-Weiss temperature of -2200 K. At low temperatures, T = 1.2 K, our diffuse neutron scattering study with polarization analysis reveals characteristic spin correlations close to a predicted two-dimensional coplanar ground state with staggered chirality. The absence of three dimensional long-range AF order proves negligible coupling between the kagome layers. The scattering intensities are consistent with high spin S=3/2 states of Co2+ in the kagome layers and low spin S=0 states for Co3+ ions at interlayer sites. Our observations agree with previous Monte Carlo simulations indicating a ground state of only short range chiral order.

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W. Schweika, M. Valldor, P. Lemmens. 2006-07-28. Approaching the ground state of the kagome antiferromagnet. https://doi.org/10.1103/physrevlett.98.067201

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