TY - JOUR
T1 - AC Magnetization of Immobilized Magnetic Nanoparticles with Different Degrees of Parallel Alignment of Easy Axes
AU - Elrefai, Ahmed L.
AU - Sasayama, Teruyoshi
AU - Yoshida, Takashi
AU - Enpuku, Keiji
N1 - Funding Information:
ACKNOWLEDGMENT This work was supported in part by Japan Society for the Promotion of Science (JSPS) Grant-in-Aid for JSPS Fellows under Grant JP18F18349.
Publisher Copyright:
© 1965-2012 IEEE.
PY - 2021/2
Y1 - 2021/2
N2 - Magnetic nanoparticles (MNPs) are physically immobilized in some biomedical applications. In this case, dynamic ac magnetization that determines MNPs' performance has strong dependence on the relative direction between the magnetic easy axes of MNPs and the applied excitation field. To study this dependence, we prepared immobilized MNP samples with different degrees of easy axes' alignment. The degree of alignment was changed by setting the strength of a dc field that is applied during the immobilization process. The magnetic properties of these samples, such as ac magnetization, coercive field, amplitude of third-harmonic signal, and hysteresis loss, are compared with those of a randomly oriented easy axes' sample. It was shown that these values are significantly affected by the degree of easy axes' alignment when the strength of the ac excitation field, H-{0} , is relatively small. The alignment effect gradually becomes smaller when H-{0} is increased. These findings are important for immobilized MNP applications in hyperthermia and magnetic particle imaging.
AB - Magnetic nanoparticles (MNPs) are physically immobilized in some biomedical applications. In this case, dynamic ac magnetization that determines MNPs' performance has strong dependence on the relative direction between the magnetic easy axes of MNPs and the applied excitation field. To study this dependence, we prepared immobilized MNP samples with different degrees of easy axes' alignment. The degree of alignment was changed by setting the strength of a dc field that is applied during the immobilization process. The magnetic properties of these samples, such as ac magnetization, coercive field, amplitude of third-harmonic signal, and hysteresis loss, are compared with those of a randomly oriented easy axes' sample. It was shown that these values are significantly affected by the degree of easy axes' alignment when the strength of the ac excitation field, H-{0} , is relatively small. The alignment effect gradually becomes smaller when H-{0} is increased. These findings are important for immobilized MNP applications in hyperthermia and magnetic particle imaging.
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U2 - 10.1109/TMAG.2020.3024864
DO - 10.1109/TMAG.2020.3024864
M3 - Article
AN - SCOPUS:85099750411
SN - 0018-9464
VL - 57
JO - IEEE Transactions on Magnetics
JF - IEEE Transactions on Magnetics
IS - 2
M1 - 9201021
ER -