Thermal Evolution of Pt-Rich FePt/Fe₃O₄ Heterodimers Studied Using X-ray Absorption Near-Edge Spectroscopy

FePt/Fe₃O₄ nanoparticles can be used as building blocks to obtain, upon thermal annealing, magnetic nanocomposites with combined magnetic properties. Although the pre- and postannealed samples are usually well-characterized, a detailed investigation during annealing is necessary to reveal the role o...

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Detalles Bibliográficos
Autores principales: Figueroa, Santiago J. A., Stewart, Silvana Jacqueline, Rueda, T., Hernando, Antonio, de la Presa, P.
Formato: Articulo Preprint
Lenguaje:Inglés
Publicado: 2011
Materias:
Física
FePt
FePt/Fe₃O₄ heterodimers
Pt L₃ XANES
Fe K-XANES
Fe₃Pt
Acceso en línea:http://sedici.unlp.edu.ar/handle/10915/142995
Aporte de:
SEDICI (UNLP) de Universidad Nacional de La Plata
id I19-R120-10915-142995
record_format dspace
institution Universidad Nacional de La Plata
institution_str I-19
repository_str R-120
collection SEDICI (UNLP)
language Inglés
topic Física
FePt
FePt/Fe₃O₄ heterodimers
Pt L₃ XANES
Fe K-XANES
Fe₃Pt
spellingShingle Física
FePt
FePt/Fe₃O₄ heterodimers
Pt L₃ XANES
Fe K-XANES
Fe₃Pt
Figueroa, Santiago J. A.
Stewart, Silvana Jacqueline
Rueda, T.
Hernando, Antonio
de la Presa, P.
Thermal Evolution of Pt-Rich FePt/Fe₃O₄ Heterodimers Studied Using X-ray Absorption Near-Edge Spectroscopy
topic_facet Física
FePt
FePt/Fe₃O₄ heterodimers
Pt L₃ XANES
Fe K-XANES
Fe₃Pt
description FePt/Fe₃O₄ nanoparticles can be used as building blocks to obtain, upon thermal annealing, magnetic nanocomposites with combined magnetic properties. Although the pre- and postannealed samples are usually well-characterized, a detailed investigation during annealing is necessary to reveal the role of intermediate processes to produce a desirable composite. We present an alternative method using in situ XANES to investigate the thermal evolution of oleic acid- and oleylamine-coated Pt-rich FePt/Fe₃O₄ heterodimers. As the temperature increases, a progressive reduction of Fe₃O₄ to FeO occurs helped by the thermolysis of the surfactants, while above 550 K Fe₃Pt starts to be formed. At 840 K an abrupt increase of FeO further drives the phase transformation to stabilize the iron platinum soft phase. Thus, the Fe₃O₄ reduction acts as catalyst that promotes the Fe and Pt interdiffusion between the Pt-rich FePt and Fe₃O₄/FeO to form Fe₃Pt instead of exchange-coupled FePt/Fe₃O₄ with hard magnetic properties. In addition, the role of the interface of the heterodimer ends is discussed. The pre- and postannealed samples were also characterized by TEM, XRD, EXAFS, magnetometry, and Mössbauer spectroscopy.
format Articulo
Preprint
author Figueroa, Santiago J. A.
Stewart, Silvana Jacqueline
Rueda, T.
Hernando, Antonio
de la Presa, P.
author_facet Figueroa, Santiago J. A.
Stewart, Silvana Jacqueline
Rueda, T.
Hernando, Antonio
de la Presa, P.
author_sort Figueroa, Santiago J. A.
title Thermal Evolution of Pt-Rich FePt/Fe₃O₄ Heterodimers Studied Using X-ray Absorption Near-Edge Spectroscopy
title_short Thermal Evolution of Pt-Rich FePt/Fe₃O₄ Heterodimers Studied Using X-ray Absorption Near-Edge Spectroscopy
title_full Thermal Evolution of Pt-Rich FePt/Fe₃O₄ Heterodimers Studied Using X-ray Absorption Near-Edge Spectroscopy
title_fullStr Thermal Evolution of Pt-Rich FePt/Fe₃O₄ Heterodimers Studied Using X-ray Absorption Near-Edge Spectroscopy
title_full_unstemmed Thermal Evolution of Pt-Rich FePt/Fe₃O₄ Heterodimers Studied Using X-ray Absorption Near-Edge Spectroscopy
title_sort thermal evolution of pt-rich fept/fe₃o₄ heterodimers studied using x-ray absorption near-edge spectroscopy
publishDate 2011
url http://sedici.unlp.edu.ar/handle/10915/142995
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