Inverted Linear Halbach Array for Separation of Magnetic Nanoparticles

• Published in: IEEE transactions on magnetics Vol. 49; no. 7; pp. 3449 - 3452
• Main Authors: Ijiri, Yumi, Poudel, Chetan, Williams, P. Stephen, Moore, Lee R., Orita, Toru, Zborowski, Maciej
• Format: Journal Article Conference Proceeding
• Language: English
• Published: New York, NY IEEE 01.07.2013; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Arrays; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Magnetic liquids; Magnetic resonance imaging; Magnetic separation; Magnetism; Magnetometers; Materials science; Nanoparticles; Other topics in materials science; permanent magnets; Physics; Saturation magnetization; Suspensions; Nanoparticles; magnetic separation; Permanent magnets; Separation; Magnetic liquids; Magnetic properties; nanoparticles; magnetic liquids; permanent magnets
• ISSN: 0018-9464; 1941-0069
• DOI: 10.1109/TMAG.2013.2244577

A linear array of Nd-Fe-B magnets has been designed and constructed in an inverted Halbach configuration for use in separating magnetic nanoparticles. The array provides a large region of relatively low magnetic field, yet high magnetic field gradient in agreement with finite element modeling calculations. The magnet assembly has been combined with a flow channel for magnetic nanoparticle suspensions, such that for an appropriate distance away from the assembly, nanoparticles of higher moment aggregate and accumulate against the channel wall, with lower moment nanoparticles flowing unaffected. The device is demonstrated for iron oxide nanoparticles with diameters of ~5 and 20 nm. In comparison to other approaches, the inverted Halbach array is more amenable to modeling and to scaling up to preparative quantities of particles.