Investigation of the magnetocaloric effect in correlated metallic systems with Van Hove singularities in the electron spectrum
- Авторлар: Igoshev P.1,2, Kokorina E.2, Nekrasov I.2
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Мекемелер:
- Institute of Metal Physics, Ural Branch
- Institute of Electrophysics, Ural Branch
- Шығарылым: Том 118, № 3 (2017)
- Беттер: 207-216
- Бөлім: Electrical and Magnetic Properties
- URL: https://journals.rcsi.science/0031-918X/article/view/166948
- DOI: https://doi.org/10.1134/S0031918X17030048
- ID: 166948
Дәйексөз келтіру
Аннотация
In this work, the magnetic contribution to the isothermal entropy change ΔS upon switching on a magnetic field has been investigated in correlated metallic ferromagnets within the Hubbard nondegenerate model. The analytical expression ΔS for obtained in the mean-field approximation depends substantially on the electronic structure (density of electron states), which presents new ways to increase the absolute value of ΔS relative to the known result obtained within the Heisenberg model. The temperature dependence of ΔS has been calculated at different values of the Coulomb interaction U and the number of electrons n for the Bethe infinite-dimensional lattice and square lattice with allowance for transfer integrals in the first (t) and the second (t') coordination shells. It has been found that the presence of Van Hove singularities in the electronic spectrum near the Fermi level makes it possible to considerably increase |ΔS| at a fixed magnetic field. The possibility of first-order magnetic phase transitions depending on the model parameters has been analyzed.
Негізгі сөздер
Авторлар туралы
P. Igoshev
Institute of Metal Physics, Ural Branch; Institute of Electrophysics, Ural Branch
Email: nekrasov@iep.uran.ru
Ресей, ul. S. Kovalevskoi 18, Ekaterinburg, 620990; ul. Amundsena 106, Ekaterinburg, 620016
E. Kokorina
Institute of Electrophysics, Ural Branch
Email: nekrasov@iep.uran.ru
Ресей, ul. Amundsena 106, Ekaterinburg, 620016
I. Nekrasov
Institute of Electrophysics, Ural Branch
Хат алмасуға жауапты Автор.
Email: nekrasov@iep.uran.ru
Ресей, ul. Amundsena 106, Ekaterinburg, 620016