Magnetostructural properties of Ho-5(Si0.8Ge0.2)(4)

TitleMagnetostructural properties of Ho-5(Si0.8Ge0.2)(4)
Publication TypeJournal Article
Year of Publication2010
AuthorsSingh NK, Paudyal D, Mudryk Y, Pecharsky VK, Gschneidner KA
Journal TitlePhysical Review B
Date Published05/01
ISBN Number1098-0121
Accession NumberISI:000278141800059
Keywordsalloys, behavior, gd-5(si2ge2), intermetallics, MAGNETIC-FIELDS, phase, temperature, thermodynamics, transition, TRANSPORT

The magnetostructural properties of Ho-5(Si0.8Ge0.2)(4) have been investigated both experimentally and by using first-principles theory. The compound orders ferromagnetically at 50 K, and in the temperature range of 50-100 K it exhibits a Griffiths phaselike behavior. The dc magnetization, heat capacity, and the relaxation and frequency dependence of the ac susceptibility indicate that the long-range magnetic order and a spin-glasslike state may coexist in Ho-5(Si0.8Ge0.2)(4) over a certain temperature range below T-C. Despite adopting the Gd5Si2Ge2-type monoclinic (M-type) structure at room temperature, the compound does not exhibit a magnetostructural transition at TC, unlike some other members of the R-5(Si1-xGex)(4) series with R=Gd, Tb, and Dy. The tight-binding linear muffin-tin orbital calculations within the local spin-density approximation show that in R-5(Si1-xGex)4 compounds the gain in the exchange energy brought about by the M-type to Gd5Si4-type orthorhombic (O-I) transformation decreases as R is changed from Gd to other heavy lanthanides and the absence of the M to O-I phase transformation in Ho-5(Si0.8Ge0.2)(4) is a result of low gain in the magnetic contribution to the total energy.

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