利用磁化响应的二次谐波进行超顺磁性纳米颗粒检测。

Superparamagnetic nanoparticle detection using second harmonic of magnetization response.

作者信息

Zhang Yi, Murata Hayaki, Hatsukade Yoshimi, Tanaka Saburo

机构信息

Department of Environmental and Life Sciences, Toyohashi University of Technology, Toyohashi, Aichi 441-8580, Japan.

出版信息

Rev Sci Instrum. 2013 Sep;84(9):094702. doi: 10.1063/1.4820447.

DOI:10.1063/1.4820447

PMID:24089845

Abstract

We introduce a method to improve the detection sensitivity for the magnetization M of superparamagnetic nanoparticles (MNP). The M response of MNP to an applied magnetic field H (M-H characteristics) could be divided into a linear region and a saturation region, which are separated at a transition point H(k). When applying an excitation magnetic field (H(ac)) with a frequency ω0 and an additional dc bias field H(dc) = H(k), the second harmonic of M reaches the maximum due to the nonlinearity of the M-H characteristics. It is stronger than any other harmonics and responsible for small H(ac) without a threshold. The second harmonic selected as the readout criterion for M response of MNP is systematically analyzed and experimentally proven.

摘要

我们介绍一种提高超顺磁性纳米颗粒（MNP）磁化强度M检测灵敏度的方法。MNP对施加磁场H的M响应（M-H特性）可分为线性区域和饱和区域，它们在一个转变点H(k)处分开。当施加频率为ω0的激励磁场H(ac)以及附加直流偏置磁场H(dc)=H(k)时，由于M-H特性的非线性，M的二次谐波达到最大值。它比任何其他谐波都更强，且在无阈值的情况下对小H(ac)起作用。作为MNP的M响应读出标准所选择的二次谐波经过了系统分析和实验验证。