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Dynamic magnetization of thermally blocked iron oxide nanoparticles characterized by a sensitive AC magnetometer using a resonant excitation coil

Mohd Mawardi, Saari and Nazatul Shareena, Suhaimi and M. H., Sulaiman and Nurul Akmal, Che Lah and Kenji, Sakai and Toshihiko, Kiwa and Keiji, Tsukada (2018) Dynamic magnetization of thermally blocked iron oxide nanoparticles characterized by a sensitive AC magnetometer using a resonant excitation coil. In: 6th Edition of International Conference On Superconductivity and Magnetism (ICSM2018), 29 April - 4 May 2018 , Premier Palace Hotel Beldibi, Antalya, Turkey. pp. 1-11.. (Unpublished)

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Abstract

In this study, a development of a sensitive AC magnetometer using a resonant Litz wire coil is reported. Using the AC magnetometer, we characterized the dynamic magnetization of thermally blocked iron oxide nanoparticles in different viscosity of carrier liquid. The multi-core iron oxide nanoparticles have a mean core size of 12 nm. The magnetization curve was measured by a specially developed high-Tc SQUID magnetometer. Using the measured dynamic magnetization, we then reconstructed the distribution of the hydrodynamic size of the particles by assuming a log-normal distribution of particle size in a Debye function of magnetic response. The AC susceptibility model by Shliomis and Stepanov which accounts for anisotropic directions of the easy axes of magnetic nanoparticles with respect to the excitation field direction, was used. The reconstructed hydrodynamic sizes agreed with the size determined from dynamic light scattering method. The peak of imaginary component of magnetization shifted to lower frequency region as viscosity increased. We showed that harmonics ratio and the lagging phase can be used to independently determine the viscosity of carrier liquid. A highly sensitive exploration of dynamics properties of magnetic nanoparticles can be expected by using the developed system.

Item Type: Conference or Workshop Item (Lecture)
Uncontrolled Keywords: Brownian relaxation; Dynamic magnetization; Iron oxide nanoparticles; Magnetometer
Subjects: T Technology > TK Electrical engineering. Electronics Nuclear engineering
T Technology > TS Manufactures
Faculty/Division: Faculty of Electrical & Electronic Engineering
Faculty of Manufacturing Engineering
Depositing User: Mrs. Neng Sury Sulaiman
Date Deposited: 29 Jun 2018 04:54
Last Modified: 29 Jun 2018 04:54
URI: http://umpir.ump.edu.my/id/eprint/21410
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