Search

In this study, we have performed the first-principles investigation of the structural, electronic, magnetic, and optical properties of TbNi, TbNiRu, and TbNiRh compounds. The full-potential linearized augmented plane waves with local orbitals method is used in the framework of density functional theory (DFT) employing the generalized gradient approximation (GGA) for the exchange correlation functional as implemented in WIEN2k package. The structural properties are reposed on the evaluation of the equilibrium lattice parameters of these compounds under hexagonal structure such as lattice constants ( a and c), bulk modulus ( B), and its first pressure derivative $(B^{\prime })$ . The spin-polarized electronic structures, including band structure and density of states, are calculated employing the GGA plus band correlated Hubbard parameter (GGA + U) scheme. The results show that density of states and magnetic moment of the pure TbNi compound are changed by doping. These changes are observed in the appearance of additional peaks on the spectral density of states (DOS) and in the augmentation of the total magnetic moment of TbNi X (X = Ru and Rh) intermetallic compounds. Based on the electronic structure results, the frequency dependents of optical conductivity are estimated in all the spectra and interpreted in the interband optical absorption part. [ABSTRACT FROM AUTHOR]

The full-Heusler alloys CoYZ (Z = P, As, Sb, and Bi) were investigated by using the state-of-the-art full-potential linearized augmented plane wave plus local orbital (FP-LAPW + lo) method within the framework of density functional theory (DFT), to understand the structural, electronic, and magnetic properties of these new Heusler alloys. The generalized gradient approximation (GGA) was chosen to define the exchange-correlation potential for studying the structural properties, whereas electronic and magnetic properties were developed by using the GGA + U scheme, where U is the Hubbard term, which explains the Coulomb repulsion and was applied to describe the ' d' electrons. The structural properties indicated that the ferromagnetic states of these compounds are energetically more favorable than the paramagnetic states. Through results on the electronic structures (band structures and densities of states), it is found that all these alloys exhibit a complete half-metallic nature, with half-metallic gaps (E) of 0.632, 0.605, 1.223, and 0.922 eV for CoYP, CoYAs, CoYSb, and CoYBi alloys, respectively. The magnetic properties indicated that the total spin magnetic moments of these Heusler alloys obey the Slater-Pauling rule around value 2 µ approximately. The local magnetic moments of Co and Y transition elements have opposite signs with different intensities, thus revealing the ferromagnetic character. Our study of both electronic and magnetic properties demonstrates in detail that CoYZ (Z = P, As, Sb, and Bi) full-Heusler alloys are complete half-metallic ferrimagnetic materials. [ABSTRACT FROM AUTHOR]