用于表征磁性纳米颗粒弛豫动力学的磁性颗粒光谱仪的设计与验证

Design and validation of magnetic particle spectrometer for characterization of magnetic nanoparticle relaxation dynamics.

作者信息

Garraud Nicolas, Dhavalikar Rohan, Maldonado-Camargo Lorena, Arnold David P, Rinaldi Carlos

机构信息

Department of Electrical and Computer Engineering, University of Florida , Gainesville, Florida 32608, USA.

Department of Chemical Engineering, University of Florida , Gainesville, Florida 32608, USA.

出版信息

AIP Adv. 2017 Mar 2;7(5):056730. doi: 10.1063/1.4978003. eCollection 2017 May.

DOI:10.1063/1.4978003

PMID:28344854

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC5336471/

Abstract

The design and validation of a magnetic particle spectrometer (MPS) system used to study the linear and nonlinear behavior of magnetic nanoparticle suspensions is presented. The MPS characterizes the suspension dynamic response, both due to relaxation and saturation effects, which depends on the magnetic particles and their environment. The system applies sinusoidal excitation magnetic fields varying in amplitude and frequency and can be configured for linear measurements (1 mT at up to 120 kHz) and nonlinear measurements (50 mT at up to 24 kHz). Time-resolved data acquisition at up to 4 MS/s combined with hardware and software-based signal processing allows for wide-band measurements up to 50 harmonics in nonlinear mode. By cross-calibrating the instrument with a known sample, the instantaneous sample magnetization can be quantitatively reconstructed. Validation of the two MPS modes are performed for iron oxide and cobalt ferrite suspensions, exhibiting Néel and Brownian relaxation, respectively.

摘要

本文介绍了一种用于研究磁性纳米颗粒悬浮液线性和非线性行为的磁性粒子光谱仪（MPS）系统的设计与验证。MPS表征了悬浮液的动态响应，这是由弛豫和饱和效应引起的，其取决于磁性颗粒及其环境。该系统施加振幅和频率可变的正弦激励磁场，并且可以配置用于线性测量（高达120 kHz时为1 mT）和非线性测量（高达24 kHz时为50 mT）。高达4 MS/s的时间分辨数据采集与基于硬件和软件的信号处理相结合，允许在非线性模式下进行高达50次谐波的宽带测量。通过用已知样品对仪器进行交叉校准，可以定量重建瞬时样品磁化强度。对分别表现出奈尔弛豫和布朗弛豫的氧化铁和钴铁氧体悬浮液进行了两种MPS模式的验证。