Temperature dependence of initial magnetic susceptibility of polydisperse ferrofluids: A critical comparison between experiment and theory

O. A. Goldina¹ - A. V. Lebedev² - A. O. Ivanov¹ - E. A. Elfimova¹

¹ Institute of Mathematics and Computer Sciences, Ural Federal University, 51 Lenin av., Ekaterinburg 620000, Russia
² Institute of Continuous Media Mechanics, UB RAS, 1 Korolyov st., Perm 614013, Russia

Abstract
Experimental temperature dependencies of the initial magnetic susceptibility for six ferrofluid samples at various concentrations are examined using two theories: well-tested second-order modified mean-field theory [5] and a new polydisperse theory [11]. It turns out that the new polydisperse theory outperforms the modified mean-field theory. The new theory demonstrates good agreement with experimental data in a broad temperature range and can predict extremely high susceptibility value χ ∼ 120 at low temperature T ∼ 240 K. Tables 2, Figs 3, Refs 17.