Abstract
The temperature variation of the low-field magnetic susceptibility χ for antiferromagnetic nanoparticles of ferritin and ferrihydrite in the superparamagnetic regime is shown to follow the equation The theoretical basis for this equation is the low-field limit of the modified Langevin variation of the magnetization M given by (H is the applied field, is the magnetic moment/particle, and is the antiferromagnetic susceptibility of the core). Self-consistent values of C, and are obtained for ferritin and ferrihydrite nanoparticles.
- Received 16 March 2001
DOI:https://doi.org/10.1103/PhysRevB.64.132410
©2001 American Physical Society