Year-end Sale % OFF 
Abstract
On the basis of a three-dimensional classical Heisenberg model with nearest magnetic neighbor interactions, and using a Monte Carlo–Metropolis dynamics, we study the magnetic behavior of a 5 nm diameter magnetite nanoparticle as a function of temperature. The nanoparticle is built by taken into account the inverse spinel structure of a stoichiometric magnetite, the valence of the iron ions (Fe 3+ A, Fe 3+ B, Fe 2+ B where A and B stand for tetrahedral and octahedral sites, respectively) as well as the different involved coordination numbers and superexchange integrals. The employed Hamiltonian includes coupling interactions between Fe ions through the integrals J AA, J AB and J BB, a Néel's surface anisotropy term applied to surface ions, and cubic magnetocrystalline anisotropy for those ions belonging to the core of the nanoparticle. Results reveal a strong influence of surface anisotropy, depending on its sign and magnitude, upon the total magnetization at low temperatures. Such results, which are summarized in a proposal of phase diagram, reveal the onset of spin structures different from a single-domain state. Differences in the thermal behavior respect to a bulk magnetite are also addressed and discussed.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
