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Electronic contribution to the enhancement of the ferromagnetic ordering temperature by Si substitution in Gd-5(SixGe1-x)(4)

TitleElectronic contribution to the enhancement of the ferromagnetic ordering temperature by Si substitution in Gd-5(SixGe1-x)(4)
Publication TypeJournal Article
Year of Publication2013
AuthorsTseng, YC, Paudyal, D, Mudryk, Y, Pecharsky, VK, Gschneidner, KA, Haskel, D
JournalPhysical Review B
Volume88
Pagination054428
Date Published08
Type of ArticleArticle
ISBN Number1098-0121
Accession NumberWOS:000323706900003
Keywordsgd-5(si2ge2)
Abstract

nsition is observed to take place with applied pressure in the paramagnetic state of a Gd-5(Si0.125Ge0.875)(4) sample at room temperature at a much smaller volume than needed to drive the same structural transition with Si doping, indicating that, even in the absence of magnetic order, electronic effects with Si doping dominate the energetics of structural transformations over lattice (volume) effects. DFT calculations show that the electronic mechanism behind this effect is a stronger Si 3p-Gd 5d than Ge 4p-Gd 5d hybridization, a critical ingredient in mediating indirect exchange interactions between localized Gd 4f spins. The results highlight the strong sensitivity of the magnetic ordering temperature to the nature of p-d hybridization, opening opportunities for tailoring the magnetocaloric properties of these compounds by substituting other p and rare-earth elements at the Si/Ge and Gd sites, respectively.

DOI10.1103/PhysRevB.88.054428
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