Europhys. Lett, 48 (2), pp. 215-220 (1999)
Inelastic polarised neutron scattering in the triangular-lattice antiferromagnet : An experimental proof of the chiral universality
V. P. Plakhty 1, S. V.
Maleyev 1, J. Kulda 2, J. Wosnitza 3
D. Visser 4 and E. Moskvin 1
1 Petersburg Nuclear Physics Institute, RAS, Gatchina - St. Petersburg, 188350
2 Institut Laue-Langevin - BP 15, 38042 Grenoble Cedex 9, France
3 Physikalisches Institut, Universität Karlsruhe - 76128 Karlsruhe, Germany
4 Department of Physics, University of Warwick - Coventry CV4 7AL, UK
(received 11 June 1999; accepted 30 August 1999)
PACS. 75.25 - Spin arrangements in magnetically ordered materials (including
neutron and spin-polarized electron studies, synchrotron-source X-ray scattering,
PACS. 75.40Gb - Dynamic properties (dynamic susceptibility, spin waves, spin diffusion, dynamic scaling, etc.).
PACS. 75.40 - Critical-point effects, specific heat, short-range order.
The temperature behaviour of the polarisation-dependent part of the differential cross-section of inelastic neutron scattering is investigated for the triangular-lattice antiferromagnet in the critical region above with the external magnetic field , applied along the hexagonal axis c, or the scattering vector Q(1/3 1/3 1). In the range of reduced temperature restricted by the resolution, this part of the cross-section, which is determined by the projection of a chiral fluctuation on the field-induced magnetisation, follows a power law of reduced temperature with the critical chiral crossover exponent . This is the first chiral critical exponent determined experimentally, which gives a direct proof of the chiral universality.
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