Thermodynamic properties of magneto-anisotropic nanoparticles

TL;DR

This paper investigates the thermodynamic equilibrium properties of non-interacting 3D magnetically anisotropic nanoparticles, analyzing how anisotropy affects magnetization, susceptibility, and energy landscapes under varying magnetic fields and temperatures.

Contribution

It provides a detailed analysis of the energy landscape and magnetic response of anisotropic nanoparticles, highlighting the role of anisotropy in their thermodynamic behavior.

Findings

Energy landscape transitions from double to single well at specific angles

Magnetization and susceptibility show non-Langevin behavior

Susceptibility indicates ferromagnetic, antiferromagnetic, and paramagnetic couplings

Abstract

The purpose of this paper is to study the thermodynamic equilibrium properties of a collection of non-interacting three-dimensional (3D) magnetically anisotropic nanoparticles in the light of classical statistical physics. Pertaining to the angular dependence ($\alpha$) of the magnetic field with the anisotropy axis, energy landscape plots are obtained which reveal a continuous transition from a double well to a single well for $\alpha=\frac{\pi}{2}$ and show asymmetric bistable shape for other values of $\alpha$. The present analysis is related with the interpretation of equilibrium magnetization and static susceptibility of nanomagnetic system as a function of external magnetic field, $B$, and temperature, $T$. The magnetization and susceptibility confirms the non Langevin behaviour of magneto-anisotropic monodomain particles. The susceptibility analysis establishes the ferromagnetic, antiferromagnetic and paramagnetic like coupling for various $\alpha$. This study reveals the essential role of magneto anisotropic energy in the interpretation of the magnetic behaviour of a collection of noninteracting single domain nanoparticles.