2016 CAP Congress / Congrès de l'ACP 2016

Surface vacancy mediated pinning of the magnetisation in $\gamma$-Fe2O3 nanoparticles: A micromagnetic simulation study$^*$

14 Jun 2016, 19:42

2m

SITE Atrium (University of Ottawa)

Poster (Non-Student) / affiche (non-étudiant) Condensed Matter and Materials Physics / Physique de la matière condensée et matériaux (DCMMP-DPMCM) DCMMP Poster Session with beer / Session d'affiches, avec bière DPMCM

Speaker

Mr Bassel Alkadour (Department of Physics and Physical Oceanography, Memorial University)

Description

Results from finite temperature stochastic LLG simulations of an atomistic core-shell model of $\gamma$-Fe$_2$O$_3$ spherical nanoparticles are presented. The radial surface anisotropy gives rise to a surface magnetisation with a Neel-like domain wall separating the magnetic poles. It is shown that the pinning of the domain wall by the oxygen anion sites plays an important role in the low temperature relaxation processes [1]. The core-shell model shows qualitative agreement with experimental results. A super-spin model with temperature-dependent anisotropy is a promising model to simulate complex hierarchical structures and the long time scale dynamics of such nanoparticles[2]. [1] T. N. Shendruk, R. D. Desautels, B. W. Southern, and J. van Lierop, Nanotechnology, vol. 18, p. 455704, 2007. [2] M. A. Kostiainen, P. Ceci, M. Fornara, P. Hiekkataipale, O. Kasyutich, R. J. M. Nolte, J. J. L. M. Cornelissen, R. D. Desautels, and J. van Lierop, ACS Nano, vol. 5, pp. 6394–6402, 2011 $^*$ Supported by NSERC