Magneto-optical harmonic susceptometry of superparamagnetic materials
Abstract
We describe a technique to optically characterize superparamagnetism. Faraday rotation measurements are performed on a superparamagnetic nanocomposite using small alternating current magnetic fields. The superparamagnetism of the iron oxide nanoparticles causes signals at the uneven harmonics of the magnetic field frequency. These signals provide information on the magnetic moment of the superparamagnetic nanoparticles. Dia- and paramagnetism do not cause signals at higher harmonics, resulting in a high sensitivity to superparamagnetism, even in samples with large dia- or paramagnetic contributions. This technique provides a rapid, economical method to characterize superparamagnetism in composite samples not easily accessible by other techniques.
- Publication:
-
Applied Physics Letters
- Pub Date:
- April 2013
- DOI:
- 10.1063/1.4801837
- Bibcode:
- 2013ApPhL.102p1903V
- Keywords:
-
- diamagnetic materials;
- iron compounds;
- magnetic moments;
- magneto-optical effects;
- nanocomposites;
- nanomagnetics;
- nanoparticles;
- paramagnetic materials;
- superparamagnetism;
- 75.20.Ck;
- 78.20.Ls;
- 75.30.Cr;
- 75.75.-c;
- 75.50.Tt;
- 78.67.Bf;
- Nonmetals;
- Magnetooptical effects;
- Saturation moments and magnetic susceptibilities;
- Fine-particle systems;
- nanocrystalline materials;
- Nanocrystals and nanoparticles