2001/04/27 by Л. А. Пономаренко, A. de Visser, Ponomarenko, L. A. +5
Biochemistry, Genetics and Molecular Biology · #FOS: Physical sciences #Magnetic and Electromagnetic Effects #Materials Science (cond-mat.mtrl-sci) #Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
paper · pdf · doi:10.48550/arxiv.cond-mat/0104539
openalex publication_date 2001/04/27 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We have calculated the low-field magnetic susceptibility χ of a system consisting of non-interacting mono-dispersed nanoparticles using a classical statistical approach. The model makes use of the assumption that the axes of symmetry of all nanoparticles are aligned and oriented at a certain angle ψ with respect to the external magnetic field. An analytical expression for the temperature dependence of the susceptibility χ(T) above the blocking temperature is obtained. The derived expression is a generalization of the Curie law for the case of anisotropic magnetic particles. We show that the normalized susceptibility is a universal function of the ratio of the temperature over the anisotropy constant for each angle ψ. In the case that the easy-axis is perpendicular to the magnetic field the susceptibility has a maximum. The temperature of the maximum allows one to determine the anisotropy energy.