Open AccessФазовые переходы в геликоидальных ферромагнетиках с концентрационными флуктуациями локальной намагниченности
Author(s) -
А.А. Повзнер,
А.Г. Волков
Publication year - 2019
Publication title -
fizika tverdogo tela
Language(s) - English
Resource type - Journals
eISSN - 1726-7498
pISSN - 0367-3294
DOI - 10.21883/ftt.2019.07.47834.387
Subject(s) - condensed matter physics , magnetization , ferromagnetism , physics , vortex , manganese , phase transition , phenomenological model , spin (aerodynamics) , magnetic field , materials science , thermodynamics , quantum mechanics , metallurgy
A phenomenological description of phase transitions induced by fluctuations in helicoidal ferromagnets with concentration fluctuations has been developed. For this, the method of the Ginzburg-Landau functional was used and random variables that are equal to unity in the place occupied by the magnetic atom and zero otherwise are introduced. It is shown that, due to concentration effects, the local magnetization is preserved above the temperature of the magnetic transition (TS), fluctuations of the spin spiral arise, and skirmion states arise in a magnetic field. The disappearance of vortex states is associated with the suppression of local magnetization by thermodynamic fluctuations at temperature TS (> TC). Theoretical results explain the reasons for the significant expansion of the temperature range of states of the skyrmion in a non-stoichiometric manganese monosilicide with manganese deficiency.