Mohd Mawardi, Saari and Nazatul Shareena, Suhaimi and Mohd Herwan, Sulaiman and Nurul Akmal, Che Lah and Sakai, Kenji and Kiwa, Toshihiko and Tsukada, Keiji (2019) Influence of viscosity on dynamic magnetization of thermally blocked iron oxide nanoparticles characterized by a sensitive AC magnetometer. Journal of Superconductivity and Novel Magnetism. pp. 1-8. ISSN 1557-1947. (Published)
|
Pdf
Influence of viscosity on dynamic magnetization of thermally blocked .pdf Download (269kB) | Preview |
Abstract
In this work, we show that the viscosity of carrier liquid affects the dynamic magnetization of thermally blocked multi-core iron oxide nanoparticles. The core size of the nanoparticles was determined from the magnetization curve measured by a specially developed high-Tc SQUID magnetometer and calculated to be 11.7 nm. Using an AC magnetometer developed based on induction coils, the dynamic magnetization of the multi-core iron oxide nanoparticle solution was measured from 3 Hz to 10.48 kHz. Later, we reconstructed of the hydrodynamic size distribution of the particles by assuming a log-normal distribution of particle size in an 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. The reconstructed hydrodynamic sizes showed an average diameter of 130 nm and agreed with the size determined by dynamic light scattering method. In the case of increasing viscosity of the carrier liquids from 0.89 to 8.11 mPa s, the dynamic magnetization peaks of the imaginary component have shifted to a lower frequency region. We showed that the harmonics ratio and phase delay upon the magnetic field excitation at 30 Hz could also be used to determine the viscosity of carrier liquid independently.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | Brownian relaxation; Dynamic magnetization; Iron oxide nanoparticles; Magnetometer |
| Subjects: | Q Science > QC Physics T Technology > TP Chemical technology |
| Faculty/Division: | Faculty of Electrical & Electronic Engineering Faculty of Manufacturing Engineering |
| Depositing User: | Mrs Norsaini Abdul Samat |
| Date Deposited: | 10 Jun 2019 03:14 |
| Last Modified: | 20 Nov 2019 03:48 |
| URI: | http://umpir.ump.edu.my/id/eprint/24706 |
| Download Statistic: | View Download Statistics |
Actions (login required)
 |
View Item |