Low temperature structural transitions in dipolar hard spheres

Autor(en)

A. O. Ivanov, S. S. Kantorovich, L. Rovigatti, J. M. Tavares, F. Sciortino

Abstrakt

We investigate the structural chain-to-ring transition at low temperature in a gas of dipolar hard spheres (DHS). Due to the weakening of entropic contribution, ring formation becomes noticeable when the effective dipole-dipole magnetic interaction increases. It results in the redistribution of particles from usually observed flexible chains into flexible rings. The concentration (ρ) of DHS plays a crucial part in this transition: at a very low ρ only chains and rings are observed, whereas even a slight increase of the volume fraction leads to the formation of branched or defect structures. As a result, the fraction of DHS aggregated in defect-free rings turns out to be a non-monotonic function of ρ. The average ring size is found to be a slower increasing function of ρ when compared to that of chains. Both theory and computer simulations confirm the dramatic influence of the ring formation on the ρ-dependence of the initial magnetic susceptibility (χ) when the temperature decreases. The rings due to their zero total dipole moment are irresponsive to a weak magnetic field and drive to the strong decrease of the initial magnetic susceptibility.

Organisation(en)

Computergestützte Physik und Physik der Weichen Materie

Externe Organisation(en)

Ural Federal University, Instituto Politécnico de Lisboa, Università degli Studi di Roma La Sapienza

Journal

Journal of Magnetism and Magnetic Materials

Band

383

Seiten

272-276

Anzahl der Seiten

5

ISSN

0304-8853

DOI

https://doi.org/10.1016/j.jmmm.2014.10.013

Publikationsdatum

06-2015

Peer-reviewed

Ja

ÖFOS 2012

103023 Polymerphysik, 103017 Magnetismus, 103029 Statistische Physik

Schlagwörter

ASJC Scopus Sachgebiete

Electronic, Optical and Magnetic Materials, Condensed Matter Physics

Link zum Portal

https://ucrisportal.univie.ac.at/de/publications/83a956fe-74a3-4442-8310-e7d526f2a25e