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Magnetostructural transition in Gd5Si0.5Ge3.5: Magnetic and x-ray powder diffraction measurements, and theoretical calculations

TitleMagnetostructural transition in Gd5Si0.5Ge3.5: Magnetic and x-ray powder diffraction measurements, and theoretical calculations
Publication TypeJournal Article
Year of Publication2008
AuthorsMudryk Y, Paudyal D, Pecharsky VK, Gschneidner KA
Journal TitlePhysical Review B
Volume77
Pages024408
Date PublishedJan
Type of ArticleArticle
ISBN Number1098-0121
Accession NumberISI:000252862600051
Keywordsbehavior, CORRELATION-ENERGY, electronic-structure, GD-5(SI0.1GE0.9)(4), gd-5(si2ge2), gd-5(sixge1-x)(4), ge, GIANT, MAGNETOCALORIC COMPOUND, MAGNETOOPTICAL PROPERTIES, magnetoresistance
Abstract

Magnetostructural transition, which occurs at 77 K (89 K) in the heat-treated (as cast) Gd5Si0.5Ge3.5, has been examined both experimentally, by magnetic and x-ray powder diffraction measurements, and theoretically, by ab initio calculations. Similar to that observed in a related Gd5Si0.4Ge3.6 alloy, this first-order phase transformation from a high-temperature Sm5Ge4-type [O(II)] phase to a low-temperature Gd5Si4-type [O(I)] phase is accompanied by an antiferromagnetic to ferromagnetic transition. The H-T phase diagram, which includes both structural and magnetic features, has been constructed. The total energy as a function of unit-cell volume calculated from first principles confirms the experimentally observed first-order nature of the magnetostructural transformation. Experimental results supported by theoretical calculations indicate that Si promotes the O(II)-Gd5Si0.5Ge3.5 to O(I)-Gd5Si0.5Ge3.5 transformation by exerting chemical pressure.
DOI10.1103/PhysRevB.77.024408
Alternate JournalPhys. Rev. B