Landau theory of the magnetic phase diagram of CsMnBr 3

1990; American Physical Society; Volume: 41; Issue: 4 Linguagem: Inglês

10.1103/physrevb.41.2543

ISSN

1095-3795

Autores

M. L. Plumer, A. Caillé,

Tópico(s)

Advanced Condensed Matter Physics

Resumo

The magnetic-field--temperature phase diagram of ${\mathrm{CsMnBr}}_{3}$ determined by recent neutron-scattering results is explained here by an investigation of a previously developed nonlocal Landau-type free energy. The degeneracy of helically and linearly polarized spin configurations at the N\'eel temperature is broken by a magnetic field and is shown to be responsible for the novel type of multicritical point observed at T=${T}_{N}$, H=0. The theory also accounts for the spin structures of the observed ordered phases as well as the temperature dependences of the phase boundaries.

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