Magnetic properties of Fe-doped organic-inorganic nanohybrids
authors Silva, NJO; Amaral, VS; Carlos, LD; Bermudez, VD
nationality International
journal JOURNAL OF APPLIED PHYSICS
keywords NANOPARTICLES; CHEMISTRY
abstract We present a magnetic study of Fe-doped diureasils (siloxane-based networks to which poly(ethylene oxide)-based chains are grafted by urea cross linkages doped with Fe(II) or Fe(III) ions. Structural studies show that the Fe(II) ions interact mainly with the organic chain, whereas the incorporation of Fe(III) leads to the formation of iron-based nanoclusters, with radius increasing from 20 to 40 A. Fe(II)-doped samples behave as simple paramagnets, with mu(eff)=5.32 mu(B). Fe(III)-doped hybrids present antiferromagnetic interactions, with T-N increasing with Fe(III) concentration up to 13.6 K for 6% doping. Thermal irreversibility was observed below similar to40 K and is stronger for higher concentrations. The coercive fields (H-C) are of the order of 1000 Oe at 5 K. Hysteresis cycles are shifted to negative fields, revealing the presence of exchange anisotropy interactions with exchange fields (H-E) of the order of 100 Oe. Both fields decrease rapidly with increasing temperature. We analyze this behavior in terms of the contribution of surface spin disorder to exchange anisotropy. (C) 2003 American Institute of Physics.
publisher AMER INST PHYSICS
issn 0021-8979
year published 2003
volume 93
issue 10
beginning page 6978
ending page 6980
digital object identifier (doi) 10.1063/1.1556163
web of science category Physics, Applied
subject category Physics
unique article identifier WOS:000182822300184
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journal analysis (jcr 2017):
journal impact factor 2.176
5 year journal impact factor 2.163
category normalized journal impact factor percentile 60.616
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