Seminar : Benoît Pichon (Institut de Physique et Chimie des Matériaux de Strasbourg) – 25/06/2021 at 11am

Abstract

Nanoparticles represent a true alternative to build high performance technological devices. At the nanoscale, the physical properties can be modulated significantly as a function of size and shape, and also by taking into account collective properties of nanoparticle arrays. In the field of nanoparticles, core-shell nanoparticles combining exchange –coupled magnetic materials with enhanced magnetic anisotropy became very attractive because they offer the possibility to circumvent one of the most striking limitations at the nanoscale : low magnetic stability against temperature resulting from size reduction. High magnetic anisotropy of nanoparticles is mandatory for further development of new rare-earth free applications such as mass storage media or sensors. We focus here on the fundamental understanding of bimagnetic nanoparticles combining a ferromagnetic Fe3-dO4 core and an antiferromagnetic CoO shell which result in enhanced magnetic anisotropy with respect to Fe3O4 nanoparticles. This material is discussed as maters of nanoparticles synthesis and assembling which rule intrinsic and collective properties, respectively. Advantages and limitations of these systems will be presented as well as, briefly, alternatives.

Recent articles :
K. Sartori et al. Nanoscale, 2019, 11, 12946
K. Sartori et al. JACS 2019, 141, 9783
M. Dolci et al. Adv. Funct. Mater. 2018, 1706957