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dc.contributor.CRUESPUniversidade Estadual de Campinaspt_BR
dc.typeArtigo de periódicopt_BR
dc.titlePressure-induced amorphization and collapse of magnetic order in the type-I clathrate Eu8Ga16Ge30pt_BR
dc.contributor.authorMardegan, JRLpt_BR
dc.contributor.authorFabbris, Gpt_BR
dc.contributor.authorVeiga, LSIpt_BR
dc.contributor.authorAdriano, Cpt_BR
dc.contributor.authorAvila, MApt_BR
dc.contributor.authorHaskel, Dpt_BR
dc.contributor.authorGiles, Cpt_BR
unicamp.authorMardegan, J. R. L. Veiga, L. S. I. Adriano, C. Giles, C. Univ Estadual Campinas, Inst Fis Gleb Wataghin, BR-13083859 Sao Paulo, Brazilpt_BR
unicamp.authorMardegan, J. R. L. Fabbris, G. Haskel, D. Argonne Natl Lab, Adv Photon Source, Argonne, IL 60439 USApt_BR
unicamp.authorFabbris, G. Washington Univ, Dept Phys, St Louis, MO 63130 USApt_BR
unicamp.authorVeiga, L. S. I. Lab Nacl Luz Sincrotron, BR-13083970 Campinas, SP, Brazilpt_BR
unicamp.authorAvila, M. A. UFABC, CCNH, BR-09210580 Sao Paulo, Brazilpt_BR
dc.description.abstractWe investigate the low temperature structural and electronic properties of the type-I clathrate Eu8Ga16Ge30 under pressure using x-ray powder diffraction (XRD), x-ray absorption near-edge structure (XANES), and x-ray magnetic circular dichroism (XMCD) techniques. The XRD measurements reveal a transition to an amorphous phase above 18 GPa. Unlike previous reports on other clathrate compounds, no volume collapse is observed prior to the crystalline-amorphous phase transition which takes place when the unit cell volume is reduced to 81% of its ambient pressure value. Fits of the pressure-dependent relative volume to a Murnaghan equation of state yield a bulk modulus B-0 = 65 +/- 3 GPa and a pressure derivative B '(0) = 3.3 +/- 0.5. The Eu L2-edge XMCD data shows quenching of the magnetic order at a pressure coincident with the crystalline-amorphous phase transition. This information along with the persistence of an Eu2+ valence state observed in the XANES spectra up to the highest pressure point (22 GPa) indicates that the suppression of XMCD intensity is due to the loss of long range magnetic order. When compared with other clathrates, the results point to the importance of guest ion-cage interactions in determining the mechanical stability of the framework structure and the critical pressure for amorphization. Finally, the crystalline structure is not found to recover after pressure release, resulting in an amorphous material that is at least metastable at ambient pressure and
dc.relation.ispartofPhysical Review Bpt_BR
dc.relation.ispartofabbreviationPhys. Rev. Bpt_BR
dc.publisher.cityCollege Pkpt_BR
dc.publisherAmer Physical Socpt_BR 16pt_BR
dc.identifier.citationPhysical Review B. Amer Physical Soc, v. 88, n. 14, 2013.pt_BR
dc.sourceWeb of Sciencept_BR
dc.description.sponsorshipFundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)pt_BR
dc.description.sponsorshipUS Department of Energy, Office of Science, Office of Basic Energy Sciences [DE-AC-02-06CH11357]pt_BR
dc.description.sponsorship1Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)pt_BR
dc.description.sponsordocumentnumberFAPESP [2009/10264-0, 2011/24166-0, 2012/10675-2, 2012/17562-9]pt
dc.description.sponsordocumentnumberUS Department of Energy, Office of Science, Office of Basic Energy Sciences [DE-AC-02-06CH11357]pt
dc.description.provenanceMade available in DSpace on 2014-07-30T18:08:05Z (GMT). No. of bitstreams: 0 Previous issue date: 2013en
dc.description.provenanceMade available in DSpace on 2015-11-26T16:33:55Z (GMT). No. of bitstreams: 0 Previous issue date: 2013en
Appears in Collections:Unicamp - Artigos e Outros Documentos

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