Eur. Phys. J. AP 22, 83-87 (2003)
https://doi.org/10.1051/epjap:2003027

Experimental investigation on γ − Fe₂O₃ nanoparticles Faraday Rotation: particles size dependence

¹ Laboratoire Dispositifs et Instrumentation en Optoélectronique et Micro-Ondes, Université Jean Monnet, 42023 St-Etienne Cedex 2, France
² Laboratoire des Liquides Ioniques et Interfaces Chargées, Université Pierre et Marie Curie, 4 place Jussieu, 75252 Paris Cedex 05, France
³ Département de Physique des Matériaux, Université Claude Bernard, 43 boulevard du 11 novembre 1918, 69622 Villeurbanne Cedex, France

Corresponding author: Francois.Royer@univ-st-etienne.fr

Received: 11 June 2002
Revised: 29 November 2002
Accepted: 4 March 2003
Published online: 6 May 2003

Abstract

Magnetooptical and optical experiments are performed on size sorted maghemite () ferrofluids. Water based ferrofluid samples are synthesised by the coprecipitation method followed by a size sorting process. All the samples have the same particles volume fraction: 0.2%. Transmittance and Faraday rotation are found to be size dependent. The saturation of the Faraday rotation is decreasing when particles mean diameter increases. Faraday rotation curves are described by orientation Langevin theory and the size dependence of their magnitude is discussed using nanoparticles internal field.