Title :
Comparative Study of Magnetic Properties of Nanoparticles by High-Frequency Heat Dissipation and Conventional Magnetometry
Author :
Malik, V. ; Goodwill, J. ; Mallapragada, S. ; Prozorov, T. ; Prozorov, R.
Author_Institution :
Ames Lab., Ames, IA, USA
Abstract :
The rate of heating of 15 nm uniformly-sized magnetic aqueous nanoparticles suspension by high-amplitude and high-frequency ac magnetic field induced by the resonating LC circuit was measured. The results are analyzed in terms of specific energy absorption rate (SAR). Fitting field amplitude and frequency dependences of SAR to the linear response theory, magnetic moment per particles was extracted. The value of magnetic moment was independently evaluated from dc magnetization measurements of a frozen colloid by fitting field-dependent magnetization to a Langevin function. The two methods produced similar results, which are compared to the theoretical expectation for this particle size. Additionally, analysis of SAR curves yielded effective relaxation time.
Keywords :
cooling; high-frequency effects; magnetic moments; magnetic particles; magnetisation; nanofabrication; nanomagnetics; nanoparticles; particle size; LC circuit; Langevin function; dc magnetization measurements; field-dependent magnetization; frequency dependence; frozen colloid; heating rate; high-amplitude ac magnetic field; high-frequency heat dissipation; linear response theory; magnetic moment; magnetic properties; magnetometry; particle size; resonating LC circuit; specific energy absorption rate; uniformly-sized magnetic aqueous nanoparticles; Magnetic hysteresis; Magnetic moments; Magnetometers; Nanoparticles; Saturation magnetization; Specific absorption rate; Magnetite Nanoparticles; Nanomagnetics; Specic Absorption Rate (SAR); magnetite nanoparticles; specific absorption rate;
Journal_Title :
Magnetics Letters, IEEE
DOI :
10.1109/LMAG.2014.2368517
