Artículo
Magnetic couplings and magnetocaloric effect in the GdTX (T=Sc, Ti, Co, Fe; X=Si, Ge) compounds
Fecha de publicación:
07/2020
Editorial:
IOP Publishing
Revista:
Journal of Physics: Condensed Matter
ISSN:
0953-8984
Idioma:
Inglés
Tipo de recurso:
Artículo publicado
Clasificación temática:
Resumen
We compute the magnetocaloric effect (MCE) in the GdTX (T = Sc, Ti, Co, Fe; X = Si, Ge) compounds as a function of the temperature and the external magnetic field. To this end we use a density functional theory approach to calculate the exchange–coupling interactions between Gd3+ ions on each compound. We consider a simplified magnetic Hamiltonian and analyze the dependence of the exchange couplings on the transition metal T, the p-block element X, and the crystal structure (CeFeSi-type or CeScSi-type). The most significant effects are observed for the replacements Ti → Sc or Fe → Co which have an associated change in the parity of the electron number in the three dimensional level. These replacements lead to an antiferromagnetic contribution to the magnetic couplings that reduces the Curie temperature and can even lead to an antiferromagnetic ground state. We solve the magnetic models through mean field and Monte Carlo calculations and find large variations among compounds in the magnetic transition temperature and in the magnetocaloric effect, in agreement with the available experimental data. The magnetocaloric effect shows a universal behavior as a function of temperature and magnetic field in the ferromagnetic compounds after a scaling of the relevant energy scales by the Curie temperature TC.
Palabras clave:
DFT
,
MAGNETOCALORIC EFFECT
,
MONTE CARLO
,
RTX COMPOUNDS
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Identificadores
Colecciones
Articulos (UE-INN - NODO BARILOCHE)
Articulos de UNIDAD EJECUTORA INSTITUTO DE NANOCIENCIA Y NANOTECNOLOGIA - NODO BARILOCHE
Articulos de UNIDAD EJECUTORA INSTITUTO DE NANOCIENCIA Y NANOTECNOLOGIA - NODO BARILOCHE
Citación
Garcia, Daniel Julio; Vildosola, Veronica Laura; Cornaglia de la Cruz, Pablo Sebastian; Magnetic couplings and magnetocaloric effect in the GdTX (T=Sc, Ti, Co, Fe; X=Si, Ge) compounds; IOP Publishing; Journal of Physics: Condensed Matter; 32; 28; 7-2020; 1-7
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