Faculté des sciences

Magnon dispersion in field-induced magnetically ordered phases

Matsumoto, Masashige ; Normand, Bruce ; Rice, T. M. ; Sigrist, Manfred

In: Journal of Magnetism and Magnetic Materials, 2004, vol. 272-276, p. 267-268

The magnon dispersion in the field-induced and pressure-induced antiferromagnetically (AF) ordered phase in TlCuCl₃ are studied. In the pressure-induced AF phase, there are two transverse phase (Goldstone) modes and one gapped longitudinal amplitude mode. A magnetic field lifts the degeneracy, and it gives rise to three separated magnon branches in the field-induced AF phase, where the lowest... Plus

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    Summary
    The magnon dispersion in the field-induced and pressure-induced antiferromagnetically (AF) ordered phase in TlCuCl₃ are studied. In the pressure-induced AF phase, there are two transverse phase (Goldstone) modes and one gapped longitudinal amplitude mode. A magnetic field lifts the degeneracy, and it gives rise to three separated magnon branches in the field-induced AF phase, where the lowest lying mode corresponds to a Goldstone mode. A model consisting of three distinct dimer sublattices is proposed to account for the plateaus which appear in magnetization curves of NH₄CuCl₃.