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Magnetic Sol-Gel Derived Poly(oxyethylene)- Siloxane Nanohybrids

Published online by Cambridge University Press:  01 February 2011

V.S. Amaral ,
L.D. Carlos ,
N.J.O. Silva ,
V. de Zea Bermudez ,
K. Dahmouche ,
C.V. Santilli ,
A.F. Craievich  and
F. Palacio
V.S. Amaral
Affiliation:
Departamento de Física and CICECO, Universidade de Aveiro, Aveiro, PORTUGAL
L.D. Carlos
Affiliation:
Departamento de Física and CICECO, Universidade de Aveiro, Aveiro, PORTUGAL
N.J.O. Silva
Affiliation:
Departamento de Física and CICECO, Universidade de Aveiro, Aveiro, PORTUGAL
V. de Zea Bermudez
Affiliation:
Departamento de Química, Univ. de Trás-os Montes e Alto Douro Vila Real, PORTUGAL
K. Dahmouche
Affiliation:
Instituto de Química/UNESP, Araraquara-SP, BRAZIL
C.V. Santilli
Affiliation:
Instituto de Química/UNESP, Araraquara-SP, BRAZIL
A.F. Craievich
Affiliation:
Instituto de Física/USP, Sao Paulo-SP, BRAZIL
F. Palacio
Affiliation:
Instituto de Ciencia de Materiales de Aragón, CSIC - Univ. de Zaragoza, Zaragoza, SPAIN.
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Abstract

The magnetic and structural properties of sol-gel derived organic/inorganic nanocomposites doped with Fe(II), Fe(III), Nd(III) and Eu (III) ions are discussed. These hybrids consist of poly(oxyethylene)-based chains grafted onto siloxane nanodomains by urea cross-linkages. Small angle X-ray scattering data show the presence of spatial correlations of siloxane domains embedded in the polymer matrix. The magnetic properties of rare-earth doped samples are determined by single ion crystal-field-splitted levels (Eu3+ J=0; Nd3+ J=9/2) and the small thermal irreversibility is mainly associated to structural effects. Fe2+-doped samples behave as simple paramagnet with residual antiferromagnetic interactions. Fe3+-doped hybrids are much more complex, with magnetic hysterisis, exchange anisotropy and thermal irreversibility at low temperatures. Néel temperatures increase up to 14K for the highest (∼5.5%) Fe3+ mass concentration.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 726: Symposium Q – Hybrid Organic-Inorganic Materials , 2002 , Q6.22
Copyright
Copyright © Materials Research Society 2002

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