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arXiv · 1206.1795

Magnetic soft modes in the locally distorted triangular antiferromagnet alpha-CaCr2O4

S. Toth·B. Lake·K Hradil·T. Guidi·K. C. Rule·M. B. Stone·A. T. M. N. Islam
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Abstract

In this paper we explore the phase diagram and excitations of a distorted triangular lattice antiferromagnet. The unique two-dimensional distortion considered here is very different from the 'isosceles'-type distortion that has been extensively investigated. We show that it is able to stabilize a 120{\deg} spin structure for a large range of exchange interaction values, while new structures are found for extreme distortions. A physical realization of this model is \alpha-CaCr2O4 which has 120{\deg} structure but lies very close to the phase boundary. This is verified by inelastic neutron scattering which reveals unusual roton-like minima at reciprocal space points different from those corresponding to the magnetic order.

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S. Toth, B. Lake, K Hradil, T. Guidi, K. C. Rule, M. B. Stone, A. T. M. N. Islam. 2012-06-08. Magnetic soft modes in the locally distorted triangular antiferromagnet alpha-CaCr2O4. https://doi.org/10.1103/physrevlett.109.127203

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