Modelling exchange bias in core/shell nanoparticles

Abstract

We present an atomistic model of a single nanoparticle with core/shell structure that takes into account its lattice strucutre and spherical geometry, and in which the values of microscopic parameters such as anisotropy and exchange constants can be tuned in the core, shell and interfacial regions. By means of Monte Carlo simulations of the hysteresis loops based on this model, we have determined the range of microscopic parameters for which loop shifts after field cooling can be observed. The study of the magnetic order of the interfacial spins for different particles sizes and values of the interfacial exchange coupling have allowed us to correlate the appearance of loop asymmetries and vertical displacements to the existence of a fraction of uncompensated spins at the shell interface that remain pinned during field cycling, offering new insight on the microscopic origin of the experimental phenomenology.

7 pages, 3 figures. Contribution presented at HMM 2007 held at Napoli 4-6 June 2007. To be published in J. Phys. Condens. Matter

References in corpus (4)

• Microscopic origin of exchange bias in core/shell nanoparticles
• Exchange Bias and Vertical Shift in CoFe2O4 nanoparticles
• Monte Carlo simulation study of exchange biased hysteresis loops in nanoparticles
• Exchange bias and asymmetric hysteresis loops from a microscopic model of core/shell nanoparticles

Cited by in corpus (8)

• Exchange bias effect in alloys and compounds
• Magnetic nanoparticles: from the nanostructure to the physical properties
• Monte Carlo investigation of a spherical ferrimagnetic core-shell nanoparticle under a time dependent magnetic field
• Investigation of bond dilution effects on the magnetic properties of a cylindrical Ising nanowire
• Particle size and cooling field dependence of exchange bias in core/shell magnetic nanoparticles
• Exchange Bias in the [CoO/Co/Pd]10 Antidot Large Area Arrays
• Thermal simulation of magnetization reversals for size-distributed assemblies of core-shell exchange biased nanoparticles
• Computational Frameworks for Patterned Two-Dimensional Magnetism