Influence of Viscosity on Dynamic Magnetization of Thermally Blocked Iron Oxide Nanoparticles Characterized by a Sensitive AC Magnetometer
Influence of Viscosity on Dynamic Magnetization of Thermally Blocked Iron Oxide Nanoparticles Characterized by a Sensitive AC Magnetometer
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DOI：
10.1007/s10948-019-5031-6
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发表时间：
2019-02
影响因子：
1.8
通讯作者：
M. M. Saari-M.;Nazatul Sharreena Suhaimi;M. Sulaiman;Nurul Akmal Che Lah;K. Sakai;T. Kiwa;K. Tsukada
中科院分区：
文献类型：
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作者：
M. M. Saari-M.;Nazatul Sharreena Suhaimi;M. Sulaiman;Nurul Akmal Che Lah;K. Sakai;T. Kiwa;K. Tsukada
在这项工作中，我们证明了载体液体的粘度影响热阻塞多核氧化铁纳米颗粒的动态磁化。利用特制的高tcsquid磁强计测量磁化曲线，计算出纳米颗粒的核心尺寸为11.7 nm。利用基于感应线圈的交流磁强计，测量了多芯氧化铁纳米粒子溶液在3 Hz ~ 10.48 kHz范围内的动态磁化强度。随后，我们通过假设Shliomis和Stepanov的交流磁化率模型中粒径的对数正态分布来重建颗粒的水动力尺寸分布，该模型考虑了磁性纳米颗粒易轴相对于激发场方向的各向异性。重建的水动力尺寸平均直径为130 nm，与动态光散射法测定的尺寸一致。当载液的黏度从0.89 mPa s增加到8.11 mPa s时，虚分量的动态磁化峰向低频区偏移。结果表明，在30 Hz的磁场激励下，谐波比和相位延迟也可以独立地确定载液的粘度。
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-TcSQUID 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.