Magnetism of Gd5Ge4 from first principles

TitleMagnetism of Gd5Ge4 from first principles
Publication TypeJournal Article
Year of Publication2007
AuthorsPaudyal D, Pecharsky VK, Gschneidner KA, Harmon BN
Journal TitlePhysical Review B
Volume75
Pages094427
Date PublishedMar
Type of ArticleArticle
ISBN Number1098-0121
Accession NumberISI:000245328500065
KeywordsAPPROXIMATION, CORRELATION-ENERGY, electronic-structure, gd-5(si2ge2), MAGNETOOPTICAL PROPERTIES, silicon, systems
Abstract

The origin of ferromagnetism appearing as a result of a magnetic-field-induced first-order phase transition in Gd5Ge4 is explored by calculating the total energy, local exchange splitting, density of states, and magnetic moments. The calculations were performed using the tight-binding linear muffin-tin orbital method within the nonlocal exchange correlation parametrization in the density functional theory including the on-site Coulomb interaction parameter. The total energy as a function of shear distortion along the a axis for two different orthorhombic structures is in agreement with experiment, indicating a first-order magnetostructural transition in Gd5Ge4. The rearrangement of Gd 5d and Ge 4p densities of states, the substantial differences in atom-projected band energies, the exchange splitting, and the magnetic moments calculated with ferromagnetic spin arrangements in the orthorhombic Sm5Ge4-type and Gd5Si4-type structures of Gd5Ge4 help to clarify the differences in the magnetic states of these two structures. Our calculations indicate that the Sm5Ge4-type structure of Gd5Ge4 is the structural ground state and that it is antiferromagnetic.

DOI10.1103/PhysRevB.75.094427
Alternate JournalPhys. Rev. B