Abstract:
LSDA + U + SO calculations of the electronic structure of helicoidal Fe$_{1-x}$Co$_{x}$Si ferromagnets within the virtual crystal approximation have been supplemented with the consideration of the Dzyaloshinski–Moriya interaction and ferromagnetic fluctuations of the spin density of collective d electrons with the Hubbard interactions at Fe and Co atoms randomly distributed over sites. The magnetic-state equation in the developed model describes helicoidal ferromagnetism and its disappearance accompanied by the occurrence of a maximum of uniform magnetic susceptibility at temperature $T_C$ and chiral fluctuations of the local magnetization at $T >T_C$. The reasons why the magnetic contribution to the specific heat at the magnetic phase transition changes monotonically and the volume coefficient of thermal expansion (VCTE) at low temperatures is negative and has a wide minimum near $T_C$ have been investigated. It is shown that the VCTE changes sign when passing to the paramagnetic state (at temperature $T_S$).
Citation:
A. A. Povzner, A. G. Volkov, T. A. Nogovitsyna, “Electronic structure and magnetic phase transition in helicoidal Fe$_{1-x}$Co$_{x}$Si ferromagnets”, Fizika Tverdogo Tela, 60:2 (2018), 227–233; Phys. Solid State, 60:2 (2018), 230–237
\Bibitem{PovVolNog18}
\by A.~A.~Povzner, A.~G.~Volkov, T.~A.~Nogovitsyna
\paper Electronic structure and magnetic phase transition in helicoidal Fe$_{1-x}$Co$_{x}$Si ferromagnets
\jour Fizika Tverdogo Tela
\yr 2018
\vol 60
\issue 2
\pages 227--233
\mathnet{http://mi.mathnet.ru/ftt9291}
\crossref{https://doi.org/10.21883/FTT.2018.02.45372.232}
\elib{https://elibrary.ru/item.asp?id=32739766}
\transl
\jour Phys. Solid State
\yr 2018
\vol 60
\issue 2
\pages 230--237
\crossref{https://doi.org/10.1134/S106378341802021X}
Linking options:
https://www.mathnet.ru/eng/ftt9291
https://www.mathnet.ru/eng/ftt/v60/i2/p227
This publication is cited in the following 2 articles:
A. A. Povzner, A. G. Volkov, T. A. Nogovitsyna, S. A. Bessonov, “Fluctuation-induced phase transitions and skyrmions in strongly correlated Fe$_{1-x}$Co$_{x}$Si with a disturbed crystal B20-type structure”, Phys. Solid State, 63:3 (2021), 377–385
A. A. Povzner, A. G. Volkov, T. A. Nogovitsyna, S. A. Bessonov, “Spin fluctuations and concentration magnetic transitions in chiral helical ferromagnets Fe$_{1-x}$Co$_{x}$Si”, Phys. Solid State, 62:1 (2020), 92–99