Dynamic correlation length growth in superspin glass: Bridging experiments and simulations

Interacting magnetic nanoparticles display a wide variety of magnetic behaviors that are now being gathered in the emerging field of supermagnetism. We have investigated how the out-of-equilibrium dynamics in the disordered superspin glass (SSG) state of a frozen ferrofluid sample is affected by texturation. Via magnetization relaxation experiments at low temperatures, we were able to estimate superspin correlation lengths for both textured and non-textured samples. The comparison with simulations and experiments on atomic spin glasses shows that the dynamic correlations in SSG's appear to develop in a way reminiscent to those in atomic spin glasses at intermediate time/length scales. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4769840]