Low-frequency complex magnetic susceptibility of magnetic composite microspheres in colloidal dispersion

[摘要] A procedure is presented to determine the permanent magnetic dipole moment of composite microspheres containing magnetic nanoparticles with a blocked magnetic dipole moment. The composite particles are dispersed in a solvent, and the complex magnetic susceptibility is measured from 0.1 to 1000 Hz using a highly sensitive new setup. Composite particles with a permanent magnetic dipole moment are revealed by a characteristic frequency that corresponds to the Brownian rotation of the microspheres. From measured susceptibility spectra, we calculate the permanent magnetic dipole moment of recently developed cobalt ferrite-doped silica and latex microspheres. (C) 2006 Elsevier B.V. All rights reserved.

[发布日期] 2007-04-01

[效力级别]  Proceedings Paper

[关键词] complex magnetic susceptibility;Brownian relaxation;magnetic dipole moment;microsphere;magnetic nanoparticle;colloidal dispersion;cobalt ferrite;silica;latex;magnetic susceptibility