Journal of Physical Studies 1(3), 441–452 (1997) DOI: https://doi.org/10.30970/jps.01.441 MAGNETISM IN URANIUM COMPOUNDS OF Th3P4 CRYSTAL STRUCTURE

Cz. Oleksy, J. Przystawa
Instytut Fizyki Teoretycznej Uniwersytetu Wrocławskiego,
Pl. Maksa Borna 9, 50-204 Wrocław, Poland

The present paper discusses the magnetism of the U$_3$X$_4$ compounds (X = P, As, Sb, Bi) in terms of an Heisenberg-type model introduced in 1987 by the authors. It contains competing single-ion and exchange isotropic and anisotropic interactions of comparable magnitude. The model is derived using a symmetry analysis of the structures and the Landau theory of phase transitions. The results of the mean-field calculations are presented, describing the spontaneous magnetisation, temperature dependence phase diagrams and behaviour of the system in the external magnetic field. Also the elementary excitations are discussed. The model provides a good description of the magnetic structures and their thermodynamic behaviour.

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