HEISENBERG ANALYTICAL-NUMERICAL MODEL OF NANOPARTICLE WITH PARAAND FERROMAGNETISM

Abstract

Two models of two- and three-layers of a magnetic nanoparticle are presented applying the Heisenberg theory with the parameter (exchange integral and closest neighbors) values for surface layers, which differ from the bulk layer values. The difference in the numbers of closest neighbors is taken into account. The corresponding distribution and partition functions are constructed. The magnetization of the particles is calculated by the conventional transition to thermodynamics. The results are illustrated by plots, representing magnetization curves and hysteresis loops for the layer contributions. The magnetization curves for both models are compared.

Keywords

• magnetic nanoparticle
• Heisenberg partition function
• magnetization curves
• hysteresis loop