Effect of hydrostatic pressure upon the magnetic transitions in the Gd-5(SixGe1-x)(4) giant magnetocaloric compounds: X-ray magnetic circular dichroism study

TitleEffect of hydrostatic pressure upon the magnetic transitions in the Gd-5(SixGe1-x)(4) giant magnetocaloric compounds: X-ray magnetic circular dichroism study
Publication TypeJournal Article
Year of Publication2007
AuthorsTseng YC, Haskel D, Lang JC, Sinogeikin S, Mudryk Y, Pecharsky VK, Gschneidner KA
Journal TitlePhysical Review B
Volume76
Pages014411
Date PublishedJul
Type of ArticleArticle
ISBN Number1098-0121
Accession NumberISI:000248487900068
KeywordsABSORPTION FINE-STRUCTURE, adiabatic temperature-change, alloys, gd-5(si2ge2), gd5si2ge2, phase, refrigeration, spectra
Abstract

The pressure dependence of the magnetic transitions in the giant magnetocaloric materials Gd-5(SixGe1-x)(4) (x=0.125,0.5) has been investigated using x-ray magnetic circular dichroism (XMCD) measurements in a diamond anvil cell (DAC). We found that the most notable features of the x-T phase diagram are also present in the P-T phase diagram. These include a nearly linear increase in Curie temperature, T-c, with increasing both x and P up to 275 K, and a discontinuity accompanied by a change in slope, dT(c)/d(x,P), at this temperature. However, the results indicate that a similar volume change results in similar to 3 times larger increase in T-c with Si doping than with pressure. Si doping, hence, does more to stabilize ferromagnetic interactions than simply uniformly reducing the unit cell volume.

DOI10.1103/PhysRevB.76.014411
Alternate JournalPhys. Rev. B