Properties of single- and multi-core magnetic nanoparticles assessed by magnetic susceptibility measurements
Characterization of structural and magnetic properties of MNP ensembles is crucial in tailoring their performance for biomedical applications. In this work, we evaluate the size distribution of magnetic cores in single- and multicore nanoparticles in water suspension using transmission electron mi...
| Main Authors: | , , , , , , |
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| Format: | Article |
| Language: | English English |
| Published: |
Elsevier Ltd
2021
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| Subjects: | |
| Online Access: | http://umpir.ump.edu.my/id/eprint/33835/ http://umpir.ump.edu.my/id/eprint/33835/1/2%20JMMM%20journal.pdf http://umpir.ump.edu.my/id/eprint/33835/7/Properties%20of%20single-%20and%20multi-core%20magnetic%20nanoparticles%20.pdf |
| Summary: | Characterization of structural and magnetic properties of MNP ensembles is crucial in tailoring their performance
for biomedical applications. In this work, we evaluate the size distribution of magnetic cores in single- and multicore
nanoparticles in water suspension using transmission electron microscopy (TEM) and static magnetization
curve, with the geometrical core size ranges from 8.3 to 40.2 nm. A reasonable core size derived from the
magnetization curve is obtained in comparison to the geometrical size from TEM image. The magnetic moment
distribution possibly reveals that the reduction of effective magnetic core size is due to the magnetization
degradation in cores. The hydrodynamic size and average anisotropy energy ratio obtained from the AC susceptibility
response of MNPs from 5 Hz to 100 kHz are also evaluated. The complex distribution of relaxation
time is constructed by applying a non-negative least square method to an AC susceptibility model that incorporates
the inter- and intra-potential-well contributions. It is found that a log-normal distribution might not
be adequate to represent the hydrodynamic size distribution reconstructed from the AC susceptibility responses
of the suspended samples. It is demonstrated that the AC susceptibility model used in this study can be used to
fairly estimate the average anisotropy energy ratio for MNP ensembles dominated by thermally blocked particles.
Moreover, it can be suggested that besides the geometrical core size, the degree of core aggregation also plays an
important role in determining the anisotropy energy ratio and effective magnetic moment. |
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