AC magnetometry with active stabilization and harmonic suppression for magnetic nanoparticle spectroscopy and thermometry

Published

December 14, 2020

Author(s)

Thinh Q. Bui, Weston L. Tew, Solomon I. Woods

Abstract

Magnetic nanoparticle (MNP) thermometry based on magnetic particle spectroscopy (MPS) is explored as a potential approach for realizing in-situ temperature measurement of 3D objects. MNP thermometry relies on the nonlinear magnetization response to an AC drive field. This nonlinear response has functional dependence on frequency and temperature, governed by the complex magnetization dynamics of MNP suspended in solution. In this work, we introduce our approach for accurate and precise AC magnetization measurements using actively stabilized drive fields ranging from DC to 5 kHz. To isolate the harmonic response of MNP from the drive field, we also perform active cancellation to reach drive field suppression up to 120 dB. Active stabilization and cancellation are utilized for real-time, sensitive measurements of AC magnetization of commercial samples, with stability on the timescale of hours. Initial results for MNP thermometry are demonstrated using this technique, and we achieved a total temperature uncertainty of 410 mK and 170 mK at 100 ms and 10 s integration time, respectively.

Citation

Journal of Applied Physics

Pub Type

Journals

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Keywords

Magnetic Nanoparticles, Magnetic Particle Spectrometer, AC Magnetometry, Magnetic Nanoparticle Thermometry

Citation

Bui, T. , Tew, W. and Woods, S. (2020), AC magnetometry with active stabilization and harmonic suppression for magnetic nanoparticle spectroscopy and thermometry, Journal of Applied Physics, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=931040 (Accessed January 24, 2025)