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arXiv · 0906.3378

Zig-zag ladders with staggered magnetic chirality in S = 3/2 compound beta-CaCr2O4

Françoise Damay·Christine Martin·Vincent Hardy·Antoine Maignan·Gilles André·Kevin Knight·Sean R. Giblin·Laurent C. Chapon
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Abstract

The crystal and magnetic structures of the S = 3/2 chain antiferromagnet beta-CaCr2O4 have been investigated by means of specific heat, magnetization, muon relaxation and neutron powder diffraction between 300K and 1.5K. Owing to the original topology of the Cr3+ magnetic lattice, which can be described as a network of triangular ladders, equivalent to chains with nearest and next-nearest neighbors interactions, evolution of the magnetic scattering intensity in this compound evidences two magnetic regimes : for 21K < T < 270K, a low-dimensionality magnetic ordering of the Cr3+ spins is observed, simultaneously with a strong contraction of the ladder legs, parallel to c. Below TN = 21K, a complex antiferromagnetic ordering is evidenced, with an incommensurate propagation vector k = (0, 0, q) (q ~ 0.477 at 1.5K), as exchange interactions between ladders become significant. This complex magnetic ordering can be described as a honeycomb-like arrangement of cycloids, running along c, with staggered chiralities. The experimental observation of this staggered chirality can be understood by taking into account antisymmetric Dzyaloshinskii-Moriya exchange terms.

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Françoise Damay, Christine Martin, Vincent Hardy, Antoine Maignan, Gilles André, Kevin Knight, Sean R. Giblin, Laurent C. Chapon. 2009-06-18. Zig-zag ladders with staggered magnetic chirality in S = 3/2 compound beta-CaCr2O4. https://doi.org/10.1103/physrevb.81.214405

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