Publication Date:
2010-09-28
Description:
An increasing number of promising applications for future technology is arising from size constraints in nanoparticles (NPs) and from the chemical manipulation of their surfaces. In this work, we analyse the finite-size and surface effects on polyacrylic acid-coated Fe 3 O 4 NPs and oleic acid-coated γ -Fe 2 O 3 NPs by studying their magnetization curves at different temperatures. The measured thermal dependence of the saturation magnetization is no longer explained by the typical T 3/2 Bloch law, yielding higher values than those expected for its exponent. When incorporated in polymeric matrixes to form magnetic transparent nanocomposites, the oleic acid-coated γ -Fe 2 O 3 NPs also deviate from Bloch’s law, but following the opposite trend observed in free coated NPs.
Print ISSN:
1364-503X
Electronic ISSN:
1471-2962
Topics:
Mathematics
,
Physics
,
Technology
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