Evolution of nematic and ferromagnetic ordering in suspensions of magnetic nanoplatelets

Author(s)
Alenka Mertelj, Borut Lampret, Darja Lisjak, Jürgen Klepp, Joachim Kohlbrecher, Martin Čopič
Abstract

Suspensions of magnetic nanoplatelets in isotropic solvents are very interesting examples of ferrofluids. It has been shown that above a certain concentration {\Phi}NI such suspensions form a ferromagnetic nematic phase, which makes this system a unique example of a dipolar fluid. The formation of a nematic phase is driven by anisotropic electrostatic and long-range dipolar magnetic interactions. Here, we present studies of the evolution of short range positional and orientational magnetic order in the suspensions with volume fractions below and above {\Phi}NI, using small angle neutron scattering (SANS). The results show that in the absence of an external magnetic field, short range positional and orientational order already exist at relatively low volume fractions. Polarized SANS revealed that the contribution of ferromagnetic ordering to the formation of the nematic phase is significant. The ferromagnetic correlations can be qualitatively explained by a simple model, which takes into account anisotropic screened electrostatic and dipolar magnetic interactions.

Organisation(s)
Physics of Functional Materials
Journal
Soft Matter
Volume
15
Pages
5412-5420
No. of pages
9
ISSN
1744-683X
DOI
https://doi.org/10.1039/C9SM00949C
Publication date
05-2019
Publication status
Published
Peer reviewed
Yes
Austrian Fields of Science 2012
103021 Optics
Keywords
cond-mat.soft
Portal url
https://ucris.univie.ac.at/portal/en/publications/evolution-of-nematic-and-ferromagnetic-ordering-in-suspensions-of-magnetic-nanoplatelets(94a4412d-faf0-4eb4-bda6-9607cf421ea5).html