Magnetostructural transition in Gd5Sb0.5Ge3.5

TitleMagnetostructural transition in Gd5Sb0.5Ge3.5
Publication TypeJournal Article
Year of Publication2009
AuthorsChernyshov AS, Mudryk Y, Paudyal D, Pecharsky VK, Gschneidner KA, Schlagel DL, Lograsso TA
Journal TitlePhysical Review B
Date Published11/01
ISBN Number1098-0121
Accession NumberISI:000272310900074
Keywordsab initio calculations, antimony alloys, crystal symmetry, exchange interactions (electron), ferromagnetic materials, gadolinium alloys, germanium alloys, ground states, magnetic susceptibility, magnetic transitions, magnetisation, solid-state phase trans

Magnetic and crystallographic properties of Gd5Sb0.5Ge3.5 were investigated using dc magnetization, ac magnetic susceptibility, and heat capacity of an oriented single crystal, combined with temperature and magnetic field dependent x-ray powder diffraction. The compound undergoes an unusual magnetostructural transition at 40 K and a nonmagnetic second-order transition around 63 K. The detailed crystallographic study of Gd5Sb0.5Ge3.5 shows that contrary to the R-5(SixGe1-x)(4) systems (R is a rare-earth metal), the structural transition occurs without shear displacements of the (2)(infinity)[R5T4] slabs (T=Si, Ge, and Sb), and a substantial volume change (-0.5%) does not lead to a change in crystallographic symmetry. The first-principles electronic structure calculations show higher interslab than intraslab ferromagnetic exchange interaction indicating that Sm5Ge4 type of structure supports a ferromagnetic ground state in Gd5Sb0.5Ge3.5.

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