Monte Carlo Study of the Influence of Dipole Interaction and Magnetic Anisotropy in Monodisperse and Nanochains Systems to Improve the Effects of Magnetic Hyperthermia

Quispe J.G.; Rojas-Ayala C.; Rojas-Tapia J.; Mendoza M.; Rojas-Sanchez J.C.; Champi A. · Brazilian Journal of Physics (2023) · DOI: 10.1007/s13538-023-01365-y

Resumen

Magnetic nanoparticles are being widely investigated for their great potential applications in drug transport, magnetic resonance imaging, and the treatment of magnetic hyperthermia. Magnetic hyperthermia consists of the destruction of cancer cells by heat, which is dissipated by nanoparticles. The assembly in the form of chains can increase the heating capacity of the nanoparticles, due to the effect of the dipole inter- actions and magnetic anisotropy. The heat dissipation power of the NPs can be studied through the hysteresis area of a system of nanoparticles whose diameter is greater than a critical diameter (D > Dc), outside the superparamagnetic regime. In this work, the Monte Carlo-Metropolis method is used to calculate the hysteresis area of various systems of nanochains, at low temperature (T = 5K), composed of spherical and cubic magnetite nanoparticles whit 20 nm of diameter. Monodisperse systems of spherical and cubic nanoparticles were also considered. Different concentrations and distribution of the anisotropy axes are considered randomly and constrained in a solid cone of δ = 200. Negative effects of inter-particle interactions on hysteresis area were observed. On the other hand, the increase in effective magnetic anisotropy has a positive effect on the hysteresis area, observing a competition between the dipole interactions and the magnetic anisotropy of the system. The sphere and cubic nanochains with random anisotropy show an increase in heating, for the entire range of applied magnetic field. The anisotropy restricted for sphere and cubic nanochains show the maximum heating capacity, but only for high magnetic field values. Furthermore, the system of cubic nanochains shows a resistance to the negative effects of concentration, where it is also observed increases in the hysteresis area in the region of low magnetic field. Finally, these results show the potential of sphere and cubic magnetic nanochains to improve the treatment of magnetic hyperthermia, and the importance role of the dipolar interactions and magnetic anisotropy for this magnetic systems.

Instituciones: Universidad Nacional Mayor de San Marcos