Static Scaling on an Interacting Magnetic Nanoparticle System

Abstract

The field dependence of the ac susceptibility of a concentrated frozen ferrofluid containing ultrafine Fe-C particles of monodisperse nature has been analyzed using static scaling. For the first time, a divergent behavior of the nonlinear susceptibility of a dipole-dipole interacting system is demonstrated. From the analysis, the critical exponents $\ensuremath{\gamma}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}4.0\ifmmode\pm\else\textpm\fi{}0.2$ and $\ensuremath{\beta}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}1.2\ifmmode\pm\else\textpm\fi{}0.1$ were extracted. The results support the existence of a low temperature spin-glass-like phase in interacting magnetic nanoparticle systems.