Observatorio de I+D+i UPM

Memorias de investigación
Artículos en revistas:
Magnetic Iron oxide nanoparticles in 10-40 nm range: composition in terms of magnetite/maghemite ratio, and effect on the magnetic properties
Año:2011
Áreas de investigación
  • Física,
  • Magnetismo
Datos
Descripción
Magnetic iron oxide nanoparticles in the 10-40 nm size range and with a reduced distribution in size have been synthesized under argon by using ammonium bases R4NOH (R = CH3, C2H5, C3H7) and a hydrothermal treatment. The size is tuned owing to the base to iron ratio and to the length of the alkyl chain R. We precipitate first ferric hydroxides at pH 1.5-2, then ferrous hydroxide at pH 5.5-6. The rapid increase of pH up to basic pH leads to the formation of magnetic iron oxide particles of 12 nm. For [base] to [Fe] ratio above 3.5, a homogeneous growth occurs during further hydrothermal treatment at 250 °C. The higher the quantity of base added and the longer the alkyl chain used, the smaller the particle size produced. For sizes above 20 nm, the Verwey transition at 120 K, characteristic of magnetite, is observed on the field cooling-zero field cooling magnetization curve. The nanoparticles can be described by a core-shell model, that is, a magnetite core surrounded by an oxidized layer close to maghemite. The fractional volume of maghemite increases as the particle size decreases so that below 20 nm, nanoparticles cannot be properly labeled as ?magnetite?.
Internacional
Si
JCR del ISI
Si
Título de la revista
Chemistry of Materials
ISSN
0897-4756
Factor de impacto JCR
6,397
Información de impacto
Volumen
23
DOI
10.1021/cm103188a
Número de revista
Desde la página
1379
Hasta la página
1386
Mes
SIN MES
Ranking
Esta actividad pertenece a memorias de investigación
Participantes
  • Autor: Oscar de Abril Torralba (UPM)
Grupos de investigación, Departamentos, Centros e Institutos de I+D+i relacionados
  • Creador: Departamento: Física e Instalaciones Aplicadas a la Edificación, al Medio Ambiente y al Urbanismo
S2i 2021 Observatorio de investigación @ UPM con la colaboración del Consejo Social UPM
Cofinanciación del MINECO en el marco del Programa INNCIDE 2011 (OTR-2011-0236)
Cofinanciación del MINECO en el marco del Programa INNPACTO (IPT-020000-2010-22)