Electronic structure, magnetic properties, and magnetostructural transition in Tb5Si2.2Ge1.8 from first principles

Article

关键词: MAGNETOOPTICAL PROPERTIES;    PHASE-RELATIONSHIPS;    HCP GD;    GD-5(SIXGE1-X)(4);    THERMODYNAMICS;    GD-5(SI2GE2);    TEMPERATURE;    CRYSTAL;    SPECTRA;    SYSTEMS;   

DOI  :  10.1103/PhysRevB.84.014421

来源: SCIE

【 摘 要 】

The electronic structure and magnetic properties of Tb5Si2.2Ge1.8 have been studied from first principles electronic structure calculations. The total energy of the ferromagnetic (FM) orthorhombic [O(I)] Tb5Si2.2Ge1.8 is lower than the total energy of the FM monoclinic (M) Tb5Si2.2Ge1.8, indicating that the FM O(I) is the ground state structure of Tb5Si2.2Ge1.8. Because of a strong 4f-5d exchange, the splitting of 5d bands of Tb atoms in the FM O(I) Tb5Si2.2Ge1.8 is greater than that in the FM M Tb5Si2.2Ge1.8, giving rise to higher 5d moments in the former. The magnetostructural transition temperature, T-M, and the isothermal magnetic entropy change, Delta S-M, have been calculated by coupling the parameters obtained from the first principles to the magnetothermodynamic models. Both T-M and Delta S-M are in good agreement with reported experimental values. The magnetic entropy change increases with decreasing magnetostructural transition temperature, which indicates a pathway toward tuning the magnitude of the magnetocaloric effect.

【 授权许可】

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