Dipolar-coupled nanoparticles with random uniaxial axes in a triangular lattice
Abstract Book of the XXIII IUPAP International Conference on Statistical Physics, Genova, Italy, (9-13 July 2007)Zusammenfassung
We investigate through Monte Carlo simulations the magnetic properties of a triangular array of magnetic nanoparticles with random uniaxial anisotropy axes. We assume a Gaussian distribution for the anisotropy strength and the particles are coupled by dipolar forces. We determine the blocking temperature of the system as a function of the ratio between the strengths of dipolar coupling and uniaxial anisotropy. We calculate the magnetization, susceptibility, specific heat and Binder cumulant as a function of temperature, and we see that, in the non-interacting case, these properties exhibit a maximum at the blocking temperature. We have also determined the dependence of the remanence and coercive field as a function of temperature and dipolar strength. At very low temperatures, the coercive field displays a minimum as a function of dipolar strength, while the remanence increases with the dipolar strength. These properties are related with the ferromagnetic character of the dipolar interactions in the two-dimensional triangular lattice.